Impact of heat stress on health-related symptoms and physiological changes among workers at a palm oil mill in Mukah, Sarawak, Malaysia

INTRODUCTION

The palm oil (PO) industry is one of the most important sectors in the Malaysian economy. Workers at PO mills are, however, at risk for a number of health and safety issues, including heat stress, as the PO is one of the industries with high heat exposure. Heat stress occurs when a person's body cannot get rid of excess heat. Heat stress can result in heat cramps, heat exhaustion, heat rash, and heat stroke. It also results in physiological and psychological changes that can have an impact on a worker's performance. Therefore, this study aimed to evaluate the impact of heat stress on health-related symptoms and physiological changes among workers in a PO mill.

MATERIALS AND METHODS

This cross-sectional study was conducted in a PO mill located in Mukah, Sarawak, Malaysia. Thirty-one workers from the four workstations (sterilizer, boiler, oil, and engine rooms) were selected as the respondents in this study. Wet Bulb Globe Thermometer was used in this study to measure the environmental temperature (WBGTin). Body core temperature (BCT), blood pressure (BP), and heart rate (HR) were recorded both before and after working in order to assess the physiological effects of heat stress on workers. A set of questionnaires were used to determine sociodemographic characteristics of the respondents and their symptoms related to heat stress. Data were then analyzed using SPSS Ver28.

RESULTS

The WBGTin was found to be above the ACGIH threshold limit value of heat stress exposure in the engine room, sterilizer, and boiler workstations (>28.0°C). Additionally, there was a significant difference in the worker's BCT in these three workstations before and after work (p<0.05). Only the systolic BP and HR of those working at the boiler workstation showed significant difference between before and after work (p<0.05). The most typical symptoms that workers experience as a result of being exposed to heat at work include headache and fatigue. However, statistical analysis using Spearman Rho's test showed that there is no correlation between heat stress level with physiological changes and health-related symptoms among study respondents (p>0.05).

CONCLUSION

Results of the present study confirmed that workers in PO mill were exposed to high temperatures while at work. Although the evidence indicates the physiological parameters in general are not significantly affected while working, it also demonstrated that worker's body adapts and acclimates to the level of heat. Even so, precautions should still be taken to reduce future heat exposure. It is recommended that a physiological study be carried out that focuses on cognitive function impairment to support the evidence regarding the effects of heat stress on PO mill workers.

Towards a standard diet-induced and biopsy-confirmed mouse model of non-alcoholic steatohepatitis: Impact of dietary fat source

BACKGROUND

The trans-fat containing AMLN (amylin liver non-alcoholic steatohepatitis, NASH) diet has been extensively validated in C57BL/6J mice with or without the Lep^ob/Lep^ob (ob/ob) mutation in the leptin gene for reliably inducing metabolic and liver histopathological changes recapitulating hallmarks of NASH. Due to a recent ban on trans-fats as food additive, there is a marked need for developing a new diet capable of promoting a compatible level of disease in ob/ob and C57BL/6J mice.

AIM

To develop a biopsy-confirmed mouse model of NASH based on an obesogenic diet with trans-fat substituted by saturated fat.

METHODS

Male ob/ob mice were fed AMLN diet or a modified AMLN diet with trans-fat (Primex shortening) substituted by equivalent amounts of palm oil [Gubra amylin NASH, (GAN) diet] for 8, 12 and 16 wk. C57BL/6J mice were fed the same diets for 28 wk. AMLN and GAN diets had similar caloric content (40% fat kcal), fructose (22%) and cholesterol (2%) level.

RESULTS

The GAN diet was more obesogenic compared to the AMLN diet and impaired glucose tolerance. Biopsy-confirmed steatosis, lobular inflammation, hepatocyte ballooning, fibrotic liver lesions and hepatic transcriptome changes were similar in ob/ob mice fed the GAN or AMLN diet. C57BL/6J mice developed a mild to moderate fibrotic NASH phenotype when fed the same diets.

CONCLUSION

Substitution of Primex with palm oil promotes a similar phenotype of biopsy-confirmed NASH in ob/ob and C57BL/6J mice, making GAN diet-induced obese mouse models suitable for characterizing novel NASH treatments.

Palm Oil on the Edge

Internationally recognized Spanish experts in the food industry, nutrition, toxicology, sustainability, and veterinary science met in Madrid on July 2018 to develop a consensus about palm oil (PO) as a food ingredient. Their aim was to provide a useful, evidence-based point of reference about PO. Scientific evidence about the role of PO in food safety, nutrition and sustainability was analyzed. Main conclusions were: (1) RSPO foundation responded to the environmental impact of palm crops. The Amsterdam Declaration pursues the use of 100% sustainable PO in Europe by 2020. Awareness about choosing sustainable products will help to maintain local economies and environments in the producing countries; (2) evidence shows that a moderate intake of PO within a healthy diet presents no risks for health. No evidence justifies any change fat intake recommendations; (3) food industry is interested in assuring safe, sustainable and high-quality products. The use of certified sustainable PO is increasing; and (4) there is no evidence associating PO consumption and higher cancer risk, incidence or mortality in humans. Tolerable daily intake (TDI) for toxic contaminants (2-and 3-monochloropropanediols (MCPDs), glycidyl esters (GEs)) have been established by JECFA and EFSA. Consequently, the European Commission has modified the Contaminants Regulation for GEs and it is still working on 3-MCPDs'.

The gut microbiota drives the impact of bile acids and fat source in diet on mouse metabolism

BACKGROUND

As the gut microbiota contributes to metabolic health, it is important to determine specific diet-microbiota interactions that influence host metabolism. Bile acids and dietary fat source can alter phenotypes of diet-induced obesity, but the interplay with intestinal microorganisms is unclear. Here, we investigated metabolic consequences of diets enriched in primary bile acids with or without addition of lard or palm oil, and studied gut microbiota structure and functions in mice.

RESULTS

In combination with bile acids, dietary lard fed to male C57BL/6N mice for a period of 8 weeks enhanced fat mass accumulation in colonized, but not in germ-free mice when compared to palm oil. This was associated with impaired glucose tolerance, lower fasting insulin levels, lower counts of enteroendocrine cells, fatty liver, and elevated amounts of hepatic triglycerides, cholesteryl esters, and monounsaturated fatty acids. Lard- and bile acid-fed mice were characterized by shifts in dominant gut bacterial communities, including decreased relative abundances of Lachnospiraceae and increased occurrence of Desulfovibrionaceae and the species Clostridium lactatifermentans and Flintibacter butyricus. Metatranscriptomic analysis revealed shifts in microbial functions, including lipid and amino acid metabolism.

CONCLUSIONS

Caution is required when interpreting data from diet-induced obesity models due to varying effects of dietary fat source. Detrimental metabolic consequences of a diet enriched with lard and primary bile acids were dependent on microbial colonization of the host and were linked to hepatic lipid rearrangements and to alterations of dominant bacterial communities in the cecum.

Pediatric Age Palm Oil Consumption

Palm oil is widely used in the food industry for its chemical/physical properties, low cost and wide availability. Its widespread use has provoked an intense debate about whether it is a potential danger to human health. In a careful review of the scientific literature, we focused on nutritional characteristics and health effects of the use of palm oil with regards to children, seeking to determine whether there is evidence that justifies fears about the health effects of palm oil. Our review showed that palm oil represents a significant source of saturated fatty acids, to which scientific evidence attributes negative health effects when used in excess, especially with regards to cardiovascular diseases. However, to date, there is no evidence about the harmful effects of palm oil on the health of children. Nevertheless, palm oil has possible ill health effects linked to its composition of fatty acids: its consumption is not correlated to risk factors for cardiovascular diseases in young people with a normal weight and cholesterol level; the elderly and patients with dyslipidaemia or previous cardiovascular events or hypertension are at a greater risk. Therefore, the matter is not palm oil itself but the fatty-acid-rich food group to which it belongs. The most important thing is to consume no more than 10% of saturated fatty acids, regardless of their origin and regardless of one’s age. Correct information based on a careful analysis of the scientific evidence, rather than a focus on a singular presumed culprit substance, should encourage better lifestyles.

Systematic review of palm oil consumption and the risk of cardiovascular disease

BACKGROUND

The high amount of saturated fatty acids (SFA) coupled with the rising availability and consumption of palm oil have lead to the assumption that palm oil contributes to the increased prevalence of cardiovascular diseases worldwide. We aimed at systematically synthesising the association of palm oil consumption with cardiovascular disease risk and cardiovascular disease-specific mortality.

METHODS

We systematically searched Central, Medline and Embase databases up to June 2017 without restriction on setting or language. We performed separate searches based on the outcomes: coronary heart disease and stroke, using keywords related to these outcomes and palm oil. We searched for published interventional and observational studies in adults (Age: >18 years old). Two investigators extracted data and a consensus was reached with involvement of a third. Only narrative synthesis was performed for all of the studies, as the data could not be pooled.

RESULTS

Our search retrieved 2,738 citations for stroke with one included study and 1,777 citations for coronary heart disease (CHD) with four included studies. Palmitic acid was reported to be associated with risk of myocardial infarction (MI) (OR 2.76; 95%CI = 1.39-5.47). Total SFA intake was reported to be not significant for risk of MI. Varying intake of fried foods, highest contributor to total SFA with 36% of households using palm oil for frying, showed no significant associations to risk of MI. Odds of developing first non-fatal acute MI was higher in palm oil compared to soybean oil with 5% trans-fat (OR = 1.33; 95%CI = 1.09-1.62) than palm oil compared to soybean oil with 22% trans-fat (OR = 1.16; 95%CI = 0.86-1.56). Nevertheless, these risk estimates were non-significant and imprecise. The trend amongst those taking staple pattern diet (characterised by higher palm oil, red meat and added sugar consumption) was inconsistent across the factor score quintiles. During the years of 1980 and 1997, for every additional kilogram of palm oil consumed per-capita annually, CHD mortality risk was 68 deaths per 100,000 (95% CI = 21-115) in developing countries and 17 deaths per 100,000 (95%CI = 5.3-29) in high-income countries, whereas stroke was associated with 19 deaths per 100,000 (95%CI = -12-49) and 5.1 deaths per 100,000 (95% CI: -1.2-11) respectively. The evidence for the outcomes of this review were all graded as very low. The findings of this review should be interpreted with some caution, owing to the lack of a pooled effect estimate of the association, significant bias in selection criteria and confounding factors, inclusion of other food items together with palm oil, and the possible out-dated trend in the ecological study.

CONCLUSION

In view of the abundance of palm oil in the market, quantifying its true association with CVD outcomes is challenging. The present review could not establish strong evidence for or against palm oil consumption relating to cardiovascular disease risk and cardiovascular disease-specific mortality. Further studies are needed to establish the association of palm oil with CVD. A healthy overall diet should still be prioritised for good cardiometabolic health.

Dietary Fatty Acids Alter Lipid Profiles and Induce Myocardial Dysfunction without Causing Metabolic Disorders in Mice

Oversupply of bulk saturated fatty acids (SFA) induces metabolic disorders and myocardial dysfunction. We investigated whether, without causing metabolic disorders, the uptake of individual dietary SFA species alters lipid profiles and induces myocardial dysfunction. C57BL/6 mice were fed various customized long-chain SFA diets (40% caloric intake from SFA), including a beef tallow (HBD), cocoa butter (HCD), milk fat (HMD) and palm oil diet (HPD), for 6 months. An isocaloric fat diet, containing medium-chain triglycerides, served as a control (CHD). Long-term intake of dietary long-chain SFA differentially affected the fatty acid composition in cardiac phospholipids. All long-chain SFA diets increased the levels of arachidonic acid and total SFA in cardiac phospholipids. The preferential incorporation of individual SFA into the cardiac phospholipid fraction was dependent on the dietary SFA species. Cardiac ceramide content was elevated in all mice fed long-chain SFA diets, while cardiac hypertrophy was only presented in mice fed HMD or HPD. We have demonstrated that the intake of long-chain SFA species differentially alters cardiac lipid profiles and induces cardiac dysfunction, without causing remarkable metabolic disorders.

Therapeutic effect of alkaloids and glycosides of colocynth seeds on liver injury, associated with metabolic syndrome in wistar rats, subject to nutritional stress

The Citrullus colocynthis, commonly called colocynth, is known because of its purgative effects and whose seeds are commonly used as certain diseases treatment, namely liver diseases, in the Mediterranean countries traditional medicine. This study aims to analyze the effect of two colocynth extracts « glycosides » and « alkaloids » on metabolic and histological disorders associated with liver function in Wistar rats (Rattus norvegicus). This pathology is due to an enriched oil palm diet. For this purpose, Wistar male rats n = 18, weighing between 130g and 150g, are divided into two lots. A control group (C) n = 6, receives a standard laboratory diet ; an experimental group (E) n = 12, receives a standard laboratory diet supplemented with palm oil. After seven months of experimentation, 8 experimental rats were sacrificed for the morphological study and the remaining 12 rats undergo a colocynth treatment (Tr) for eight weeks. They are subdivided into: The first six experimental rats receive a 70mg/kg single intraperitoneal injection of ethanol extract of cucurbitacin glycosides (Glc). The second lot receives a 70mg/kg single intraperitoneal injection of total alkaloids extract (Alc). The animals of (E) group showed hyperglycemia, hyperinsulinemia, hyperlipemia, dyslipoproteinemia, a significant increase of the enzymatic activity of transaminase (AST and ALT) and alkaline phosphatase (ALP). Histological examination of the liver gland shows major damages Non-alcoholic steatohepatitis [NASH]. Treatment with colocynth glycosides and alkaloids reveals a significant improvement at different levels in plasma as well as in tissue. Treatment with colocynth glycosides and alkaloids shows a hypoglycemic effect, lipid-lowering a well as a hepato-protective effect.

Dietary determinants of serum total cholesterol among middle-aged and older adults: a population-based cross-sectional study in Dar es Salaam, Tanzania

OBJECTIVE

To assess the dietary determinants of serum total cholesterol.

DESIGN

Cross-sectional population-based study.

SETTING

Peri-urban region of Dar es Salaam, Tanzania.

PARTICIPANTS

347 adults aged 40 years and older from the Dar es Salaam Urban Cohort Hypertension Study.

MAIN OUTCOME MEASURE

Serum total cholesterol measured using a point-of-care device.

RESULTS

Mean serum total cholesterol level was 204 mg/dL (IQR 169-236 mg/dL) in women and 185 mg/dL (IQR 152-216 mg/dL) in men. After adjusting for demographic, socioeconomic, lifestyle and dietary factors, participants who reported using palm oil as the major cooking oil had serum total cholesterol higher by 15 mg/dL (95% CI 1 to 29 mg/dL) compared with those who reported using sunflower oil. Consumption of one or more servings of meat per day (p for trend=0.017) and less than five servings of fruits and vegetables per day (p for trend=0.024) were also associated with higher serum total cholesterol. A combination of using palm oil for cooking, eating more than one serving of meat per day and fewer than five servings of fruits and vegetables per day, was associated with 46 mg/dL (95% CI 16 to 76 mg/dL) higher serum total cholesterol.

CONCLUSIONS

Using palm oil for cooking was associated with higher serum total cholesterol levels in this peri-urban population in Dar es Salaam. Reduction of saturated fat content of edible oil may be considered as a population-based strategy for primary prevention of cardiovascular diseases.