Effects of Yogurt and Fermented-Then-Pasteurized Milk on Lactose Absorption in an Institutionalized Elderly Group

The management of lactose intolerance among primary care physicians and its correlation with management by gastroenterologists: the SEPD-SEMG national survey

INTRODUCTION AND AIMS

The understanding of lactose intolerance (LI) is limited in some professional settings. Sociedad Española de Patología Digestiva (SEPD) and Sociedad Española de Medicina General (SEMG) have developed a survey in order to: a) Analyze primary care physicians (PCPs) knowledge and clinical management; and b) to compare results with those of a previous survey of Spanish gastroenterologists (GEs).

MATERIAL AND METHODS

An online questionnaire was sent to SEMG members with 27 items on various issues: Demographics, occupational characteristics, outlook on LI, diagnostic tests, treatment, and follow-up. Results were compared to those from a survey of GEs.

RESULTS

A total of 456 PCPs responded, versus 477 GEs. PCPs had an older mean age and longer professional experience. Level of understanding of LI was similar, albeit a higher proportion of PCPs lacked epidemiological awareness (p < 0.01). GEs tended to consider LI a "minor" condition (71.3 vs. 40.1%; p > 0.001), and LI symptoms as overlapping those of irritable bowel syndrome (93.5 vs. 88.2%; p = 0.005), although symptoms perceived as suspicious of LI were similar in both groups. Dietary recommendations were recognized as the primary therapeutic approach.

CONCLUSION

This study reveals the outlook of PCPs on LI, and allows comparison with that of GEs, as a basis for the development of strategies aimed at improving LI understanding, approach and management in our setting.

Should yoghurt cultures be considered probiotic?

Probiotics are live micro-organisms that when administered in adequate amounts confer a health benefit on the host. Consumption of yoghurt has been shown to induce measurable health benefits linked to the presence of live bacteria. A number of human studies have clearly demonstrated that yoghurt containing viable bacteria (Streptococcus thermophilusandLactobacillus delbrueckiisp.bulgaricus) improves lactose digestion and eliminates symptoms of lactose intolerance. Thus, these cultures clearly fulfil the current concept of probiotics.

Live bacterial cells as orally delivered therapeutics

Despite the swift escalation in research regarding the use of live bacterial cells for therapeutic purposes, the prophylactic and curative use of probiotic microorganisms still remains a wide and controversial field. In addition, the acknowledgement that live bacterial cells can be genetically engineered to synthesise products that have therapeutic potential has generated substantial interest among clinicians and health professionals. Clinical trials have increasingly provided an insightful scientific derivation for the use of live bacterial cells in medicinal practice in diseases such as diarrhoea, cancer, Crohn's disease, enhancement of the host's immune response, and numerous other diseases. A key constraint in the use of live bacterial cells, however, is the complexity of delivering them to the correct target sites. Oral delivery of free live cells, lyophilised cells and immobilised cells has been attempted, but with restricted success, chiefly because bacterial cells are unable to survive passage through the gastrointestinal tract in sufficient dosage. On many occasions, when given orally, these cells have been found to provoke immunogenic responses that are undesirable. Recent studies show that these problems can be overcome by delivering live bacterial cells using artificial cell microcapsules. This review abridges recent developments in the therapeutic use of live bacterial cells, addresses the potential and restrictions for their application in therapy, and provides insights into the future course of this emerging therapy.

Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus survive gastrointestinal transit of healthy volunteers consuming yogurt

To date, there is significant controversy as to the survival of yogurt bacteria (namely, Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus) after passage through the human gastrointestinal tract. Survival of both bacterial species in human feces was investigated by culture on selective media. Out of 39 samples recovered from 13 healthy subjects over a 12-day period of fresh yogurt intake, 32 and 37 samples contained viable S. thermophilus (median value of 6.3 x 10(4) CFU g(-1) of feces) and L. delbrueckii (median value of 7.2 x 10(4)CFU g(-1) of feces), respectively. The results of the present study indicate that substantial numbers of yogurt bacteria can survive human gastrointestinal transit.

Streptococcus thermophilus is able to produce a beta-galactosidase active during its transit in the digestive tract of germ-free mice

This work presents data on the application of a bacterial luciferase used to monitor gene expression of Streptococcus thermophilus in the digestive tract. The main result is that the bacterium was able to produce an active beta-galactosidase in the digestive tract, although it did not multiply during its transit. This production was enhanced when lactose (the inducer) was added to the diet.

Hydrogen excretion upon ingestion of dairy products in lactose-intolerant male subjects: importance of the live flora

OBJECTIVE

To assess the effects of the ingestion of milk, yoghurt (10(8) bacteria/ml), heat-treated yoghurt (<15 bacteria/ml) and two products obtained by dilution of yoghurt with heat-treated product (10(6) and 10(5) bacteria/ml) on hydrogen production and symptoms of lactose intolerance in lactose malabsorbers.

DESIGN

Double-blind, randomised cross-over design.

SETTING

The study was performed in the phase 1 clinical unit of OPTIMED, Nancy, France.

SUBJECTS

Twenty-four male lactose malabsorbers were selected for the study.

INTERVENTIONS

Hydrogen production and adverse events were followed during 8 h after ingestion of the products.

RESULTS

The results clearly demonstrate that ingestion of yoghurt with 10(8) bacteria/ml leads to lower H(2) excretion and complaints than the other products. Results observed with the products containing a reduced population of live flora remain better than those observed with milk.

CONCLUSIONS

The importance of a high population of the live flora is underlined.

Probiotics--compensation for lactase insufficiency

Yogurt and other conventional starter cultures and probiotic bacteria in fermented and unfermented milk products improve lactose digestion and eliminate symptoms of intolerance in lactose maldigesters. These beneficial effects are due to microbial beta-galactosidase in the (fermented) milk product, delayed gastrointestinal transit, positive effects on intestinal functions and colonic microflora, and reduced sensitivity to symptoms. Intact bacterial cell walls, which act as a mechanical protection of lactase during gastric transit, and the release of the enzyme into the small intestine are determinants of efficiency. There is a poor correlation between lactose maldigestion and intolerance; in some studies, low hydrogen exhalation without significant improvement of clinical symptoms was observed. Probiotic bacteria, which by definition target the colon, normally promote lactose digestion in the small intestine less efficiently than do yogurt cultures. They may, however, alleviate clinical symptoms brought about by undigested lactose or other reasons.

Chronic consumption of fresh but not heated yogurt improves breath-hydrogen status and short-chain fatty acid profiles: a controlled study in healthy men with or without lactose maldigestion

BACKGROUND

Ingestion of fermented dairy products induces changes in the equilibrium and metabolism of the intestinal microflora and may thus have beneficial effects on the host.

OBJECTIVE

We compared the effects of chronic consumption of yogurt with (fresh) or without (heated) live bacterial cultures (Lactobacillus bulgaricus and Streptococcus thermophilus) on plasma glucose, insulin, triacylglycerols, cholesterol, fatty acids, and short-chain fatty acids.

DESIGN

Two groups of 12 healthy men with or without lactose malabsorption were selected with use of a breath-hydrogen test after a 30-g lactose load. Subjects were randomly assigned in a crossover design to 500 g/d of either fresh or heated yogurt for 2 periods of 15 d each, separated by a 15-d washout interval.

RESULTS

Chronic consumption of fresh or heated yogurt had no detrimental effects on plasma glucose, insulin, or fatty acid areas under the curve in response to acute ingestion of 500 g yogurt in healthy men with or without lactose malabsorption. There were also no detectable changes in fasting plasma glucose, insulin, fatty acid, triacylglycerol, or cholesterol concentrations. In contrast, plasma butyrate was higher (P: < 0.03) and plasma propionate tended to be higher (P: = 0.059) in subjects without lactose malabsorption after fresh yogurt consumption than after heated yogurt consumption. There were no significant changes in plasma acetate. In subjects with lactose malabsorption, 15 d of fresh yogurt consumption also increased propionate production compared with values at baseline (P: < 0.04). In the same group, the production of breath hydrogen was lower after fresh yogurt consumption than after heated yogurt consumption (P: < 0.01).

CONCLUSIONS

In men with lactose malabsorption, chronic consumption of yogurt containing live bacterial cultures ameliorated the malabsorption, as evidenced by lower breath-hydrogen excretion, but increased propionate concentrations. In subjects without lactose malabsorption, such yogurt tended to increase propionate and increased butyrate.

Allaying fears and fallacies about lactose intolerance

Public awareness and misunderstandings of lactose intolerance are at an all-time high. Many people erroneously believe they are lactose intolerant or develop gastrointestinal symptoms after intake of lactose. Consequently, lactose-containing foods such as milk and other dairy foods may be eliminated unnecessarily from the diet. Because these foods are a major source of calcium, low intake of them can compromise calcium nutriture. This, in turn, can increase the risk of major chronic diseases such as osteoporosis (porous bones) and hypertension. This review is intended to help dietetics professionals alleviate clients' fears about lactose intolerance and recommend dietary strategies to improve tolerance to lactose. Scientific findings indicate that the prevalence of lactose intolerance is grossly overestimated. Other physiologic and psychologic factors can contribute to gastrointestinal symptoms that mimic lactose intolerance. Scientific findings also indicate that people with laboratory-confirmed low levels of the enzyme lactase can consume 1 serving of milk with a meal or 2 servings of milk per day in divided doses at breakfast and dinner without experiencing symptoms. Several dietary strategies are available to help lactose maldigesters include milk and other dairy foods in their diet without experiencing symptoms.

[Lactose intolerance and consumption of milk and milk products]

The disaccharide lactose is present as a natural component of foods only in milk and dairy products. In the gastrointestinal tract, lactose is hydrolysed by the enzyme beta-galactosidase (lactase) into glucose and galactose. These components are absorbed. With the exception of the caucasian race, the lactase activity decreases in most people at an age of 4 to 6 years. Lactose intake can cause symptoms of bloating, flatulence, abdominal pain, and diarrhea due to the lactose reaching the large intestine. This phenomenon is called lactose intolerance. It is generally recommended to those persons that they refrain from the consumption of milk and dairy products. However, most lactose intolerant people are able to digest small amounts of milk. They can also consume cheese that contains no (hard and semi-hard) or only small amounts of lactose (present in only 10% of soft cheeses). These products are very important sources of calcium. Compared to milk, the lactose content of yogurt is usually lower by about one third. Studies during the last 10 years have shown that in spite of its lactose content yogurt is very well tolerated by lactose intolerant persons. This advantage is ascribed to the presence of living lactic acid bacteria in fermented dairy products which survive passage through the stomach and also to the lactase present in these products.