Some unique biologic characteristics of the Masai of East Africa

Saturated fat in an evolutionary context

Evolutionary perspectives have yielded profound insights in health and medical sciences. A fundamental recognition is that modern diet and lifestyle practices are mismatched with the human physiological constitution, shaped over eons in response to environmental selective pressures. This Darwinian angle can help illuminate and resolve issues in nutrition, including the contentious issue of fat consumption. In the present paper, the intake of saturated fat in ancestral and contemporary dietary settings is discussed. It is shown that while saturated fatty acids have been consumed by human ancestors across time and space, they do not feature dominantly in the diets of hunter-gatherers or projected nutritional inputs of genetic accommodation. A higher intake of high-fat dairy and meat products produces a divergent fatty acid profile that can increase the risk of cardiovascular and inflammatory disease and decrease the overall satiating-, antioxidant-, and nutrient capacity of the diet. By prioritizing fiber-rich and micronutrient-dense foods, as well as items with a higher proportion of unsaturated fatty acids, and in particular the long-chain polyunsaturated omega-3 fatty acids, a nutritional profile that is better aligned with that of wild and natural diets is achieved. This would help prevent the burdening diseases of civilization, including heart disease, cancer, and neurodegenerative conditions. Saturated fat is a natural part of a balanced diet; however, caution is warranted in a food environment that differs markedly from the one to which we are adapted.

Pattern of Surgical Diseases Affecting Females in a Teaching Hospital in Central India: A Demographic Study

Introduction  Despite progress in eliminating the social and health disparity between men and women during the last century, gender equality remains an elusive goal, particularly in the developing world. This gender-based bias has been found to directly result into poor health outcome in females. Hence, it is vital to know the number and pattern of surgical diseases affecting females in any setup, so as to improve their admission rates and reach out to this neglected half of population. Materials and Methods  This was a demographic study done at a teaching hospital in Central India from January to June 2020. Data of patients discharged from female surgery ward were collected from medical record department. Age, diagnosis, urban-rural distribution, and length of hospital stay of patients were noted, and data were analyzed statistically. Results  A total of 187 patient records were studied, which revealed that the mean age of the patients was 40.35 years; maximum patients were of gastrointestinal surgery (53.42%) in which the most common diagnosis was cholelithiasis (25.13%). Urological diseases (15.50%), breast diseases (12.83%), perianal disease (9.09%), and thyroid diseases (5.34%) were found in decreasing order of frequency. Overall hospital stays of patients ranged from 1 to 14 days with average stay of 6.35 days. Conclusion  In our study, cholelithiasis was found to be the most common surgically treated disease followed by urological diseases. Breast symptoms, although commonly affecting females, did not turn into admissions as there remains a social taboo attached to it. Breast cancer still presents late, despite being the most common cancer in females in India. Approximately 65% patients were discharged within first 5 days of their admission, which indicates good hospital care and improves patient satisfaction levels. Still there is greater need for public health efforts to improve the monitoring, safety, and availability of surgical services to female patients.

Understanding health disparities affecting people of West Central African descent in the United States: An evolutionary perspective

Human populations adapting to diverse aspects of their environment such as climate and pathogens leave signatures of genetic variation. This principle may apply to people of West Central African descent in the United States, who are at increased risk of certain chronic conditions and diseases compared to their European counterparts. Less well known is that they are also at reduced risk of other diseases. While discriminatory practices in the United States continue to affect access to and the quality of healthcare, the health disparities affecting African Americans may also be due in part to evolutionary adaptations to the original environment of sub-Saharan Africa, which involved continuous exposure to the vectors of potentially lethal endemic tropical diseases. Evidence is presented that these organisms selectively absorb vitamin A from the host, and its use in parasite reproduction contributes to the signs and symptoms of the respective diseases. These evolutionary adaptations included (1) sequestering vitamin A away from the liver to other organs, to reduce accessibility to the invaders; and (2) reducing the metabolism and catabolism of vitamin A (vA), causing it to accumulate to subtoxic concentrations and weaken the organisms, thereby reducing the risk of severe disease. However, in the environment of North America, lacking vA-absorbing parasites and with a mainly dairy-based diet that is high in vA, this combination of factors is hypothesized to lead to the accumulation of vA and to increased sensitivity to vA as a toxin, which contribute to the health disparities affecting African Americans. vA toxicity is linked to numerous acute and chronic conditions via mitochondrial dysfunction and apoptosis. Subject to testing, the hypothesis suggests that the adoption of traditional or modified West Central African-style diets that are low in vA and high in vA-absorbing fiber hold promise for disease prevention and treatment, and as a population-based strategy for health maintenance and longevity.

From Oncological Paradigms to Non-Communicable Disease Pandemic. The Need of Recovery Human Biology Evolution

The paradigm of the Somatic Mutation Theory (SMT) is failing, and a new paradigm is underway but not yet established. What is being challenged is a conceptual approach that involves the entire human biology and the development of chronic diseases. The behavior of breast and other solid cancers is compatible with the concept that the primary tumor is able to control its microscopic metastases, in the same way that an organ (e.g., the liver) is able to control its physiological size. This finding suggested that cancer and its metastases may behave as an organoid. The new paradigm under construction considers the origin of tumors as a disturbance in the communication network between tissue cell populations and between cells and extracellular matrix, and supports a systemic approach to the study of both healthy and pathologic tissues. The commentary provides a rationale for the role of physical exercise in the control of tumor dormancy according to a human evolutionary perspective.

Phospholipid packing defects and oxysterols in atherosclerosis: Dietary prevention and the French paradox

The research literature on atherosclerosis includes findings investigating the atherosclerotic effect of oxysterols, which are the oxidation products of cholesterol; and the literature on oxysterols refers to mechanisms by which oxysterols cause phospholipid packing defects in cell membranes. This review synthesizes these two bodies of research findings to describe how oxysterols cause phospholipid packing defects within the membranes of vascular endothelial cells, potentially increasing cell permeability of low-density lipoprotein cholesterol which may lead to atheroma formation. Exogenous sources of oxysterols are provided by dietary intake of animal-based foods that contain cholesterol oxidation products. This review proposes an explanation for the anti-atherosclerotic effect of plant-based dietary patterns, which is attributed to restriction or avoidance of dietary oxysterol intake from animal-based foods. Furthermore, raw-milk cheeses play an important role in the traditional French diet-low oxysterol content in these unheated foods may contribute to the French paradox, in which reduced coronary heart disease is associated with a diet high in saturated fat and cholesterol.

Mediterranean diet: The role of long-chain ω-3 fatty acids in fish; polyphenols in fruits, vegetables, cereals, coffee, tea, cacao and wine; probiotics and vitamins in prevention of stroke, age-related cognitive decline, and Alzheimer disease

The mechanisms of action of the dietary components of the Mediterranean diet are reviewed in prevention of cardiovascular disease, stroke, age-associated cognitive decline and Alzheimer disease. A companion article provides a comprehensive review of extra-virgin olive oil. The benefits of consumption of long-chain ω-3 fatty acids are described. Fresh fish provides eicosapentaenoic acid while α-linolenic acid is found in canola and soybean oils, purslane and nuts. These ω-3 fatty acids interact metabolically with ω-6 fatty acids mainly linoleic acid from corn oil, sunflower oil and peanut oil. Diets rich in ω-6 fatty acids inhibit the formation of healthier ω-3 fatty acids. The deleterious effects on lipid metabolism of excessive intake of carbohydrates, in particular high-fructose corn syrup and artificial sweeteners, are explained. The critical role of the ω-3 fatty acid docosahexaenoic acid in the developing and aging brain and in Alzheimer disease is addressed. Nutritional epidemiology studies, prospective population-based surveys, and clinical trials confirm the salutary effects of fish consumption on prevention of coronary artery disease, stroke and dementia. Recent recommendations on fish consumption by pregnant women and potential mercury toxicity are reviewed. The polyphenols and flavonoids of plant origin play a critical role in the Mediterranean diet, because of their antioxidant and anti-inflammatory properties of benefit in type-2 diabetes mellitus, cardiovascular disease, stroke and cancer prevention. Polyphenols from fruits and vegetables modulate tau hyperphosphorylation and beta amyloid aggregation in animal models of Alzheimer disease. From the public health viewpoint worldwide the daily consumption of fruits and vegetables has become the main tool for prevention of cardiovascular disease and stroke. We review the important dietary role of cereal grains in prevention of coronary disease and stroke. Polyphenols from grapes, wine and alcoholic beverages are discussed, in particular their effects on coagulation. The mechanisms of action of probiotics and vitamins are also included.

Cholesterol cholelithiasis: part of a systemic metabolic disease, prone to primary prevention

Cholesterol gallstone disease have relationships with various conditions linked with insulin resistance, but also with heart disease, atherosclerosis, and cancer. These associations derive from mechanisms active at a local (i.e. gallbladder, bile) and a systemic level and are involved in inflammation, hormones, nuclear receptors, signaling molecules, epigenetic modulation of gene expression, and gut microbiota. Despite advanced knowledge of these pathways, the available therapeutic options for symptomatic gallstone patients remain limited. Therapy includes oral litholysis by the bile acid ursodeoxycholic acid (UDCA) in a small subgroup of patients at high risk of postdissolution recurrence, or laparoscopic cholecystectomy, which is the therapeutic radical gold standard treatment. Cholecystectomy, however, may not be a neutral event, and potentially generates health problems, including the metabolic syndrome. Areas covered: Several studies on risk factors and pathogenesis of cholesterol gallstone disease, acting at a systemic level have been reviewed through a PubMed search. Authors have focused on primary prevention and novel potential therapeutic strategies. Expert commentary: The ultimate goal appears to target the manageable systemic mechanisms responsible for gallstone occurrence, pointing to primary prevention measures. Changes must target lifestyles, as well as experimenting innovative pharmacological tools in subgroups of patients at high risk of developing gallstones.

The Role of Diet in the Pathogenesis of Cholesterol Gallstones

Cholesterol gallstone disease is a major health problem in Westernized countries and depends on a complex interplay between genetic factors, lifestyle and diet, acting on specific pathogenic mechanisms. Overweigh, obesity, dyslipidemia, insulin resistance and altered cholesterol homeostasis have been linked to increased gallstone occurrence, and several studies point to a number of specific nutrients as risk- or protective factors with respect to gallstone formation in humans. There is a rising interest in the identification of common and modifiable dietetic factors that put the patients at risk of gallstones or that are able to prevent gallstone formation and growth. In particular, dietary models characterized by increased energy intake with highly refined sugars and sweet foods, high fructose intake, low fiber contents, high fat, consumption of fast food and low vitamin C intake increase the risk of gallstone formation. On the other hand, high intake of monounsaturated fats and fiber, olive oil and fish (ω-3 fatty acids) consumption, vegetable protein intake, fruit, coffee, moderate alcohol consumption and vitamin C supplementation exert a protective role. The effect of some confounding factors (e.g., physical activity) cannot be ruled out, but general recommendations about the multiple beneficial effects of diet on cholesterol gallstones must be kept in mind, in particular in groups at high risk of gallstone formation.

Telocytes: New Players in Gallstone Disease

Cholesterol gallstone disease is highly prevalent in Western countries, particularly in women and some specific ethnic groups. The mechanisms behind the formation of gallstones are not clearly understood, but gallbladder dysmotility seems to be a key factor that triggers the precipitation of cholesterol microcrystals from supersaturated lithogenic bile.Given that newly described interstitial cells, telocytes, are present in the gallbladder and they are located in close vicinity of smooth muscle cell and neural fibers possibly interfering with gallbladder motility or contractility, authors are trying to summarize the current knowledge on the role of telocytes with respect to disturbed gallbladder function in gallstone disease.

Gallstones

Gallstone disease is a worldwide medical problem, but the incidence rates show substantial geographical variation, with the lowest rates reported in African populations. Publications in English language on gallstones which were obtained from reprint requests and PubMed database formed the basis for this paper. Data extracted from these sources included authors, country, year of publication, age and sex of patients, pathogenesis, risk factors for development of gallstones, racial distribution, presenting symptoms, complications and treatment. Gallstones occur worldwide, however it is commonest among North American Indians and Hispanics but low in Asian and African populations. High biliary protein and lipid concentrations are risk factors for the formation of gallstones, while gallbladder sludge is thought to be the usual precursor of gallstones. Biliary calcium concentration plays a part in bilirubin precipitation and gallstone calcification. Treatment of gallstones should be reserved for those with symptomatic disease, while prophylactic cholecystectomy is recommended for specific groups like children, those with sickle cell disease and those undergoing weight-loss surgical treatments. Treatment should be undertaken for a little percentage of patients with gallstones, as majority of those who harbor them never develop symptoms. The group that should undergo cholecystectomy include those with symptomatic gallstones, sickle cell disease patients with gall stones, and patients with morbid obesity who are undergoing laparotomy for other reasons.

A multidisciplinary reconstruction of Palaeolithic nutrition that holds promise for the prevention and treatment of diseases of civilisation

Evolutionary medicine acknowledges that many chronic degenerative diseases result from conflicts between our rapidly changing environment, our dietary habits included, and our genome, which has remained virtually unchanged since the Palaeolithic era. Reconstruction of the diet before the Agricultural and Industrial Revolutions is therefore indicated, but hampered by the ongoing debate on our ancestors' ecological niche. Arguments and their counterarguments regarding evolutionary medicine are updated and the evidence for the long-reigning hypothesis of human evolution on the arid savanna is weighed against the hypothesis that man evolved in the proximity of water. Evidence from various disciplines is discussed, including the study of palaeo-environments, comparative anatomy, biogeochemistry, archaeology, anthropology, (patho)physiology and epidemiology. Although our ancestors had much lower life expectancies, the current evidence does neither support the misconception that during the Palaeolithic there were no elderly nor that they had poor health. Rather than rejecting the possibility of 'healthy ageing', the default assumption should be that healthy ageing posed an evolutionary advantage for human survival. There is ample evidence that our ancestors lived in a land-water ecosystem and extracted a substantial part of their diets from both terrestrial and aquatic resources. Rather than rejecting this possibility by lack of evidence, the default assumption should be that hominins, living in coastal ecosystems with catchable aquatic resources, consumed these resources. Finally, the composition and merits of so-called 'Palaeolithic diets', based on different hominin niche-reconstructions, are evaluated. The benefits of these diets illustrate that it is time to incorporate this knowledge into dietary recommendations.

Lactase persistence and lipid pathway selection in the Maasai

The Maasai are a pastoral people in Kenya and Tanzania, whose traditional diet of milk, blood and meat is rich in lactose, fat and cholesterol. In spite of this, they have low levels of blood cholesterol, and seldom suffer from gallstones or cardiac diseases. Field studies in the 1970s suggested that the Maasai have a genetic adaptation for cholesterol homeostasis. Analysis of HapMap 3 data using Fixation Index (Fst) and two metrics of haplotype diversity: the integrated Haplotype Score (iHS) and the Cross Population Extended Haplotype Homozygosity (XP-EHH), identified genomic regions and single nucleotide polymorphisms (SNPs) as strong candidates for recent selection for lactase persistence and cholesterol regulation in 143-156 founder individuals from the Maasai population in Kinyawa, Kenya (MKK). The non-synonmous SNP with the highest genome-wide Fst was the TC polymorphism at rs2241883 in Fatty Acid Binding Protein 1(FABP1), known to reduce low density lipoprotein and tri-glyceride levels in Europeans. The strongest signal identified by all three metrics was a 1.7 Mb region on Chr2q21. This region contains the genes LCT (Lactase) and MCM6 (Minichromosome Maintenance Complex Component) involved in lactase persistence, and the gene Rab3GAP1 (Rab3 GTPase-activating Protein Catalytic Subunit), which contains polymorphisms associated with total cholesterol levels in a genome-wide association study of >100,000 individuals of European ancestry. Sanger sequencing of DNA from six MKK samples showed that the GC-14010 polymorphism in the MCM6 gene, known to be associated with lactase persistence in Africans, is segregating in MKK at high frequency (∼58%). The Cytochrome P450 Family 3 Subfamily A (CYP3A) cluster of genes, involved in cholesterol metabolism, was identified by Fst and iHS as candidate loci under selection. Overall, our study identified several specific genomic regions under selection in the Maasai which contain polymorphisms in genes associated with lactase persistence and cholesterol regulation.

Vitamin D status indicators in indigenous populations in East Africa

PURPOSE

Sufficient vitamin D status may be defined as the evolutionary established circulating 25-hydroxyvitamin D [25(OH)D] matching our Paleolithic genome.

METHODS

We studied serum 25(OH)D [defined as 25(OH)D₂ + 25(OH)D₃] and its determinants in 5 East African ethnical groups across the life cycle: Maasai (MA) and Hadzabe (HA) with traditional life styles and low fish intakes, and people from Same (SA; intermediate fish), Sengerema (SE; high fish), and Ukerewe (UK; high fish). Samples derived from non-pregnant adults (MA, HA, SE), pregnant women (MA, SA, SE), mother-infant couples at delivery (UK), infants at delivery and their lactating mothers at 3 days (MA, SA, SE), and lactating mothers at 3 months postpartum (SA, SE). Erythrocyte docosahexaenoic acid (RBC-DHA) was determined as a proxy for fish intake.

RESULTS

The mean ± SD 25(OH)D of non-pregnant adults and cord serum were 106.8 ± 28.4 and 79.9 ± 26.4 nmol/L, respectively. Pregnancy, delivery, ethnicity (which we used as a proxy for sunlight exposure), RBC-DHA, and age were the determinants of 25(OH)D. 25(OH)D increased slightly with age. RBC-DHA was positively related to 25(OH)D, notably 25(OH)D₂. Pregnant MA (147.7 vs. 118.3) and SE (141.9 vs. 89.0) had higher 25(OH)D than non-pregnant counterparts (MA, SE). Infant 25(OH)D at delivery in Ukerewe was about 65 % of maternal 25(OH)D.

CONCLUSIONS

Our ancient 25(OH)D amounted to about 115 nmol/L and sunlight exposure, rather than fish intake, was the principal determinant. The fetoplacental unit was exposed to high 25(OH)D, possibly by maternal vitamin D mobilization from adipose tissue, reduced insulin sensitivity, trapping by vitamin D-binding protein, diminished deactivation, or some combination.

Traditionally living populations in East Africa have a mean serum 25-hydroxyvitamin D concentration of 115 nmol/l

Cutaneous synthesis of vitamin D by exposure to UVB is the principal source of vitamin D in the human body. Our current clothing habits and reduced time spent outdoors put us at risk of many insufficiency-related diseases that are associated with calcaemic and non-calcaemic functions of vitamin D. Populations with traditional lifestyles having lifelong, year-round exposure to tropical sunlight might provide us with information on optimal vitamin D status from an evolutionary perspective. We measured the sum of serum 25-hydroxyvitamin D₂ and D₃ (25(OH)D) concentrations of thirty-five pastoral Maasai (34 (SD 10) years, 43 % male) and twenty-five Hadzabe hunter-gatherers (35 (SD 12) years, 84 % male) living in Tanzania. They have skin type VI, have a moderate degree of clothing, spend the major part of the day outdoors, but avoid direct exposure to sunlight when possible. Their 25(OH)D concentrations were measured by liquid chromatography-MS/MS. The mean serum 25(OH)D concentrations of Maasai and Hadzabe were 119 (range 58-167) and 109 (range 71-171) nmol/l, respectively. These concentrations were not related to age, sex or BMI. People with traditional lifestyles, living in the cradle of mankind, have a mean circulating 25(OH)D concentration of 115 nmol/l. Whether this concentration is optimal under the conditions of the current Western lifestyle is uncertain, and should as a possible target be investigated with concomitant appreciation of other important factors in Ca homeostasis that we have changed since the agricultural revolution.

Comparison with ancestral diets suggests dense acellular carbohydrates promote an inflammatory microbiota, and may be the primary dietary cause of leptin resistance and obesity

A novel hypothesis of obesity is suggested by consideration of diet-related inflammation and evolutionary medicine. The obese homeostatically guard their elevated weight. In rodent models of high-fat diet-induced obesity, leptin resistance is seen initially at vagal afferents, blunting the actions of satiety mediators, then centrally, with gastrointestinal bacterial-triggered SOCS3 signaling implicated. In humans, dietary fat and fructose elevate systemic lipopolysaccharide, while dietary glucose also strongly activates SOCS3 signaling. Crucially however, in humans, low-carbohydrate diets spontaneously decrease weight in a way that low-fat diets do not. Furthermore, nutrition transition patterns and the health of those still eating diverse ancestral diets with abundant food suggest that neither glycemic index, altered fat, nor carbohydrate intake can be intrinsic causes of obesity, and that human energy homeostasis functions well without Westernized foods containing flours, sugar, and refined fats. Due to being made up of cells, virtually all "ancestral foods" have markedly lower carbohydrate densities than flour- and sugar-containing foods, a property quite independent of glycemic index. Thus the "forgotten organ" of the gastrointestinal microbiota is a prime candidate to be influenced by evolutionarily unprecedented postprandial luminal carbohydrate concentrations. The present hypothesis suggests that in parallel with the bacterial effects of sugars on dental and periodontal health, acellular flours, sugars, and processed foods produce an inflammatory microbiota via the upper gastrointestinal tract, with fat able to effect a "double hit" by increasing systemic absorption of lipopolysaccharide. This model is consistent with a broad spectrum of reported dietary phenomena. A diet of grain-free whole foods with carbohydrate from cellular tubers, leaves, and fruits may produce a gastrointestinal microbiota consistent with our evolutionary condition, potentially explaining the exceptional macronutrient-independent metabolic health of non-Westernized populations, and the apparent efficacy of the modern "Paleolithic" diet on satiety and metabolism.

Dietary patterns, food and macronutrient intakes among adults in three ethnic groups in rural Kenya

Objective

To compare dietary patterns and food and macronutrient intakes among adults in three ethnic groups in rural Kenya.

Design

In the present cross-sectional study, dietary intake was estimated in adult volunteers using two non-consecutive interactive 24 h recalls. Dietary patterns were assessed from the number of meals and snacks per day and from the food items and major food groups registered, and their contribution to energy intake (EI) was calculated. Anthropometric values were measured and sociodemographic data obtained using a questionnaire.

Setting

A cross-sectional study was conducted in the Bondo, Kitui and Transmara districts of rural Kenya. A high prevalence of food insecurity in Kenya underlines the importance of describing the dietary patterns and intakes in different Kenyan ethnic groups.

Subjects

A total of 1163 (61 % women) adult Luo, Kamba and Maasai, with a mean age of 38·6 (range: 18–68) years, volunteered to participate.

Results

Dietary patterns and food groups contributing to EI differed significantly among the ethnic groups. Mean EI ranged from 5·8 to 8·6 MJ/d among women and from 7·2 to 10·5 MJ/d among men, with carbohydrates contributing between 55·7 % and 74·2 % and fat contributing between 14·5 % and 30·2 % of total EI. Mean protein intake ranged from 0·72 to 1·3 g/kg per d, and EI:BMR ratio ranged between 1·1 and 1·6 in both sexes, and was highest among the Luo. Prevalence of underweight (BMI < 18·5 kg/m2) was 13·7 %, 20·5 % and 24·2 % in the Luo, Kamba and Maasai, respectively.

Conclusions

The degree of food insecurity measured as a degree of undernutrition and as dietary patterns differed considerably among the ethnic groups. The Maasai and Kamba in particular were exposed to food insecurity.

The effect of alcohol, tobacco and caffeine consumption and vegetarian diet on gallstone prevalence

AIM

To investigate the effects of alcohol, tobacco and caffeine consumption and of vegetarian diet on gallstone prevalence in an urban population sample.

METHODS

A total of 2417 individuals underwent ultrasound examination and completed a standardized questionnaire as part of the EMIL study. Statistical analysis of the data considered the known risk factors of age, female sex, BMI, positive family history and potential confounders, such as alcohol, caffeine and tobacco consumption and vegetarian diet using multiple logistic regression with variable selection.

RESULTS

The prevalence of gallstones in the population sample was 8% (171 out of 2147). Findings of the study confirmed the classic risk factors of age, female sex, obesity and positive family history. After the variable selection of potential risk factors in a logistic regression that was adjusted for age, female sex, BMI and positive family history, the factors like tobacco [odds ratio (OR) 1.09, 95% confidence interval (CI): 0.76-1.56, P=0.64] and caffeine consumption (OR: 0.77, 95% CI: 0.42-1.42, P=0.40) as well as vegetarian diet (OR: 1.14, 95% CI: 0.39-3.35, P=0.81) had no effect on gallstone prevalence. A protective effect against development of gallstones was shown for alcohol consumption (OR: 0.67, 95% CI: 0.46-0.99, P=0.04).

CONCLUSION

The factors like tobacco and caffeine consumption as well as vegetarian diet exerted no measurable effect on the prevalence of gallstones. A protective effect was found for alcohol consumption.

Epidemiology of gallstones

Gallstones are common with prevalences as high as 60% to 70% in American Indians and 10% to 15% in white adults of developed countries. Ethnic differences abound with a reduced frequency in black Americans and those from East Asia, while being rare in sub-Saharan Africa. Certain risk factors for gallstones are immutable: female gender, increasing age, and ethnicity/family (genetic traits). Others are modifiable: obesity, the metabolic syndrome, rapid weight loss, certain diseases (cirrhosis and Crohn disease), gallbladder stasis (from spinal cord injury or drugs, such as somatostatin), and lifestyle.

Hypothesis: is lactose a dietary risk factor for ischaemic heart disease?

The prevalence of primary adult lactose malabsorption (LM) in 23 ethnic groups was matched with national data on milk consumption and mortality rates from ischaemic heart disease (HD). In 6 other ethnic groups prevalence of LM was related to unquantified assessments of milk consumption and frequency of IHD. On the available data, populations with a prevalence of LM over 30%, and whose consumption of milk is low or is largely in low lactose form, have a lower risk of IHD mortality than populations with a prevalence of LM under 30% and a high milk consumption. There is evidence against attributing these findings to genetic linkage between susceptibility to IHD mortality and persistent lactose absorption, or to differences in socio-economic development, cigarette consumption or intake of animal fats. The findings are compatible with an hypothesis that, if the correlation reported previously between milk consumption and IHD mortality is causal, lactose could be the responsible dietary factor.

Obesity and regional fat distribution in Kenyan populations: impact of ethnicity and urbanization

BACKGROUND

Obesity is increasing rapidly in Africa, and may not be associated with the same changes in body composition among different ethnic groups in Africa.

OBJECTIVE

To assess abdominal visceral and subcutaneous fat thickness, prevalence of obesity, and differences in body composition in rural and urban Kenya.

SUBJECTS AND METHODS

In a cross-sectional study carried out among Luo, Kamba and Maasai in rural and urban Kenya, abdominal visceral and subcutaneous fat thicknesses were measured by ultrasonography. Height and weight, waist, mid-upper arm circumferences, and triceps skinfold thickness were measured. Body mass index (BMI), arm fat area (AFA) and arm muscle area (AMA) were calculated.

RESULTS

Among 1430 individuals (58.3% females) aged 17-68 years, abdominal visceral and subcutaneous fat, BMI, AFA and waist circumference (WC) increased with age, and were highest in the Maasai and in the urban population. AMA was only higher with increasing age among males. The prevalence of overweight (BMI > or = 25) (39.8% vs. 15.8%) and obesity (BMI > or = 30) (15.5% vs. 5.1%) was highest in the urban vs. rural population.

CONCLUSION

Abdominal visceral and subcutaneous fat thickness was higher with urban residency. A high prevalence of overweight and obesity was found. The Maasai had the highest overall fat accumulation.

Health and disease in unacculturated Amerindian populations

The stereotype of uncontacted tribal populations is that they must reproduce at near capacity to maintain or slightly increase their numbers. This paper argues that the health of minimally contacted Amerindians, as judged by the results of physical examinations and life tables for the Yanomama of Southern Venezuela and Northern Brazil, is relatively good, with population control a feature of the Indian culture. It is further argued that the usual deterioration in health with contacts with western culture probably does not result so much from special innate susceptibilities to certain epidemic diseases and to the diets and 'stresses' of civilization as from the epidemiological characteristics of newly contacted peoples.

Apolipoprotein E genotype and gallbladder disease risk in a large population-based cohort

PURPOSE

The aim of the study is to describe the association between apolipoprotein E (apoE) genotype and gallbladder disease incidence.

METHODS

Cases of incident hospitalized gallbladder disease were ascertained in nearly 13,000 middle-aged men and women participating in the Atherosclerosis Risk in Communities (ARIC) Study, a prospective cohort study in four US communities.

RESULTS

Between the ARIC baseline examination (1987 to 1989) and December 31, 2001, a total of 639 participants were hospitalized for gallbladder disease. After adjustment for age, sex, race, obesity, plasma lipid level, and diabetes, the relative risk for hospitalized gallbladder disease associated with the presence of an epsilon4 allele (i.e., genotypes E4/4, E3/4, and E2/4 versus other genotypes) was 0.72 (95% confidence interval [CI], 0.60-0.87). Stratification by race showed that the inverse association with epsilon4 was stronger in whites (relative risk, 0.69; 95% CI, 0.56-0.85) than African Americans (relative risk, 0.86; 95% CI, 0.58-1.30). The presence of the other rare isoform, epsilon2 (i.e., genotypes E2/2, E2/3, and E2/4 versus others) was associated with a modest increased risk for gallbladder disease (relative risk, 1.28; 95% CI, 1.05-1.57).

CONCLUSIONS

These results suggest that independent of traditional risk factors, apoE genotype may influence gallbladder disease risk, particularly in whites. The exact biologic mechanism for such an association remains unclear and requires further investigation.

Gallstone disease: Epidemiology of gallbladder stone disease

Gallstone disease is common: >700,000 cholecystectomies and costs of approximately 6.5 billion dollars annually in the U.S. The burden of disease is epidemic in American Indians (60-70%); a corresponding decrease occurs in Hispanics of mixed Indian origin. Ten to fifteen per cent of white adults in developed countries harbour gallstones. Frequency is further reduced in Black Americans, East Asia and sub-Saharan Africa. In developed countries, cholesterol gallstones predominate; 15% are black pigment. East Asians develop brown pigment stones in bile ducts, associated with biliary infection or parasites, or in intrahepatic ducts (hepatolithiasis). Certain risk factors for gallstones are immutable: female gender, increasing age and ethnicity/family (genetic traits). Others are modifiable: obesity, the metabolic syndrome, rapid weight loss, certain diseases (cirrhosis, Crohn's disease) and gallbladder stasis (from spinal cord injury or drugs like somatostatin). The only established dietary risk is a high caloric intake. Protective factors include diets containing fibre, vegetable protein, nuts, calcium, vitamin C, coffee and alcohol, plus physical activity.

Hyperinsulinemia, dyslipidemia, and obesity as risk factors for hospitalized gallbladder disease. A prospective study

PURPOSE

Prospective studies of gallbladder disease have investigated a limited number of risk factors and have been conducted predominantly in women. Determinants of hospitalized gallbladder disease were examined in a large, population-based cohort of men and women.

METHODS

Subjects, aged 45-64 years, were participants in the Atherosclerosis Risk in Communities (ARIC) Study who reported no history of gallbladder disease at baseline (n = 12,773). Incident cases of gallbladder disease were identified through surveillance of hospital discharges between the baseline visit (1987-1989) and 1996.

RESULTS

The crude incidence rate of hospitalized gallbladder disease was 3.8 per 1000 person-years. In women, increasing risk was observed for increasing levels of body-mass index and waist-to-hip ratio, whereas in men, increased risk was observed only in the morbidly obese (BMI >or= 35). Fasting serum insulin, low HDL cholesterol, elevated triglycerides, and hormone replacement therapy were all positively associated with gallbladder disease risk. The relative risks associated with having one, two, or three or more components of the "multiple metabolic syndrome" in men were 1.45 (95% CI = 0.9-2.3), 2.17 (1.3-3.6), and 2.34 (1.3-4.3), respectively.

CONCLUSIONS

In men, hyperinsulinemia and dyslipidemia may have some role in the etiology of gallbladder disease beyond their association with obesity, whereas in women, increased body size, central adiposity, and hormone replacement therapy may be more important determinants of gallbladder disease.

beta-casein A1, ischaemic heart disease mortality, and other illnesses

The risk factors identified with cardiovascular disease studied in the WHO MONICA project have been shown to have a limited relationship with the coronary heart disease mortality rates between centres, and in mirroring the historical rise and decline in deaths from the disease. Here we show that correlation of the calculated consumption of the milk protein, beta-casein A1 (excluding milk protein in cheese) against ischaemic heart disease (IHD) mortality has a r2 = 0.86. In the states of the former West Germany, where the breed composition of regional cattle herds has remained virtually constant since the 1950s, IHD mortality by state correlates with the estimated consumption of beta-casein A1. Information on other recognized dietary risk factors does not indicate any significant regional difference. Similarly, the populations of Toulouse in France and Belfast in Northern Ireland have almost identical collective 'traditional' risk factors for heart disease, yet the respective mortality rates vary more than threefold. People from Northern Ireland are estimated to consume 3.23 times more beta-casein A1, excluding cheese, than the French. The remarkable agreement between mortality and the consumption of this allele suggests that this factor is worthy of serious consideration as a potential source of cardiovascular disease when taken in conjunction with regional variations in the traditional risk factors. beta-casein A1 consumption also correlates strongly with type 1 diabetes incidence in 0-14-year-olds, suggesting that IHD and diabetes may share at least one causative risk factor.

The Chemical Ecology of Human Ingestive Behaviors

▪ Abstract  Ingested nutrients and nonnutrients are presented as determinants in human evolution. The amount and quality of energy, including fat, various foods supply are important criteria in governing selection. Oxidative stress associated with respiration of energy is a factor in the etiology of dietary diseases, such as cardiovascular disease and cancer, and in aging. Evolutionary trends such as gains in brain and body sizes, greater ingestion of long-chain polyunsaturated fatty acids and cholesterol, heating of fatty food, and greater longevity increased oxidative stress while greater reliance on animals foods and less on plants decreased ingestion of exogenous antioxidants. The hypothesis that selection for nonnutrient ingestive behaviors was a compensatory mechanism for increasing antioxidants is presented within the context of a four-factor model on the origins of human medicine.

Saponins and phenolic content in plant dietary additives of a traditional subsistence community, the Batemi of Ngorongoro District, Tanzania

Reports of plants added to milk and meat-based soups by the Maasai and Batemi in East Africa support a role for phenolic antioxidants and hypocholesterolemic agents in the diet, and provide explanation of the low incidence of cardiovascular disease of populations that traditionally consume high levels of dietary fat and cholesterol. Plant food additives used by the Batemi of Ngorongoro District, Tanzania, were tabulated, based on interviews with 22 informants, while 17 specimens were collected in the field and analyzed for saponin and phenolic content. A total of 81% of the Batemi additives and 82% of those known to be used by the Maasai contain potentially hypocholesterolemic saponins and/or phenolics.

Prevalence of gallstones in sonographic surveys worldwide

The use of diagnostic sonography allows determination of the prevalence of gallstones in a representative sample of the general population. The objective of this article is to review the reports of sonographically based studies of gallstone prevalence in the world literature. All available published epidemiologic studies on the prevalence of cholecystolithiasis as determined by diagnostic sonography are summarized. The sonographically based studies published to date confirm that there are significant regional differences in the prevalence of gallstones. Certain risk factors, notably age and heredity, are present worldwide.

Comparative morphology of the gallbladder and biliary tract in vertebrates: variation in structure, homology in function and gallstones

A review of investigations on the morphology of the gallbladder and biliary tract in fish, reptiles, amphibians, birds, and mammals was performed. Scanning electron microscopy, transmission electron microscopy, and light microscopy observations by the authors were also included. Variations in the presence or absence of a gallbladder, surface epithelium of the gallbladder, and differences in the morphology of the biliary tract in vertebrates were reported. Many differences were diet-related. Despite some dissimilarities observed, analogous functioning of the biliary system was accomplished by its various components, with the biliary ducts performing the function of the gallbladder when this organ was absent. In addition, the occurrence of peculiar parasitism and gallstones among some cases of vertebrates, including humans, was presented.

Pathogenesis of gallstones

The many developments in nonoperative methods for the treatment of gallstone disease underscore the importance of understanding the pathogenesis of these stones. Elucidation of the factors responsible for nucleation of crystals and the mechanism by which it occurs would appear to be the challenge if we are to define the cascade of events that results in gallstone formation.

Comparative prevalence of gallstone disease at 100-year interval in a large Romanian town, a necropsy study

The prevalence of gallstone disease in a large Romanian town was determined on 6275 necropsies performed during a 10-year period (1973-1982). The "crude" prevalence of gallstone disease in women was 17.1% and in men, 6.9%. Age-standardized prevalence was 8.4% in women and 5.0% in men. This rate is lower than the prevalence of gallstones in northern or central European countries, but it is higher than that established in some southern countries of Europe. A comparison of the "crude" prevalence of gallstone disease was compared with that calculated for a similar 10-year period 100 years ago (1873-1882), on 1538 necropsies performed in the same town. Prevalence of gallstones rose significantly in a century (from a mean of 1.2% to 11.3%; P less than 0.001), a finding consistent with the concept that gallstone disease is a "disease of civilization."

Fertility control and population growth among the Maasai

"This paper inquires into the reasons for the comparatively lower fertility and population growth among the Maasai (than among other Kenyan communities, particularly cultivators). It hypothesizes that a number of factors including male elder control of society, sexually transmitted diseases, seasonal food shortages, and general environmental health hazards all act together to suppress fertility. This situation must certainly change with further socioeconomic progress."

Milk and arteriosclerosis

Milk consumption is related to arteriosclerosis. Recent landmark studies confirm a previously suspected close correlation between milk intake and arteriosclerotic heart disease. Support is therefore provided for a recently proposed novel hypothesis that arteriosclerosis is a chronic infectious disease caused by blue-green bacteria and that milk is a carrier vehicle for these contaminant organisms. A revisionist view of diet and milk in the causation of arteriosclerosis is developed. Previous hypotheses relating milk consumption to arteriosclerosis and advances in pasteurization techniques are discussed and integrated with this infection theory.