Review of the week’s plant-based nutrition news 15th November 2020
This week I cover studies on the consumption of eggs, salmon, green tea and coffee, a randomised study of vitamin D & omega-3 supplements and I highlight a new report on the UK food system.
IMPACT OF EGG CONSUMPTION ON BLOOD LIPIDS: This has always been a controversial topic. Eggs for a longtime have been considered a ‘perfect food’ being a source of ‘complete’ protein whilst providing a number of micronutrients and vitamins such as vitamin B12, vitamin A, vitamin D, selenium, calcium, zinc and choline. Eggs are also lower in saturated fat compared to other animal foods. For most people already eating a typical Western diet, the high cholesterol in eggs does not impact blood cholesterol levels as much as previously thought. In fact eggs may elevate the ‘good’ cholesterol levels, HDL-cholesterol. However, the interpretation of many studies on eggs is clouded by the fact that they are funded by the egg industry and despite the studies showing unfavourable impacts on blood lipid levels, those funded by the egg industry seem to downplay the effects.
The study highlighted brings us an up to date systematic review and meta-analysis of randomised controlled studies of egg consumption and the impact on a number of blood lipid markers; Total cholesterol (TC), LDL-cholesterol (LDL-C), HDL-cholesterol (HDL-C), triglyceride (TG), very low-density lipoprotein cholesterol (VLDL-C), LDL-C/HDL-C, TC/HDL-C, apolipoprotein (apo)A1, and apoB100. Of note, in recent years, studies have suggested that evaluation of plasma apoA1 (primary protein in HDL-C particles) and apoB100 (primary protein in LDL-C particles) may be more sensitive and specific measures as risk factors for cardiovascular disease as increased ratio of apoB100/apoA1 has been observed, despite normal total and LDL-C. The study includes 66 randomised controlled trials with 3,185 participants and specifically investigated the impact of dose.
The results showed that egg consumption can significantly increase the blood levels of TC, LDL-C, HDL-C, TC/HDL-C ratio, apoA1, and apoB100 but does not significantly influence TG, VLDL, and LDL-C/HDL-C ratio. The increase in blood lipids was more pronounced in healthy populations and in participants who consumed greater than one egg per day. There was a linear effect of egg consumption on TC, HDL-C, TG, ApoA1, ApoB100, VLDL-C, and LDL-C/HDL-C but not for LDL-C, and TC/HDL-C. There is also variability in individual responses to egg consumption and blood lipids with some being hypo, normal or hyper-responders. The overall findings suggest that consuming 1 egg or less may be fine for most people when considering the impact on blood lipid levels.
It has to be remembered though that egg consumption is not necessary or desirable in the diet. There are better choices to make. Those eating a 100% plant-based diet/vegan diet have the lowest levels of blood cholesterol and significantly lower risk of cardiovascular disease. Of course, if eggs are replacing red and processed meat in the diet then there will be a positive effect on health. Eating eggs instead of beans and lentils or as part of cakes and pastries will have a negative impact on health. Eggs by law are not allowed to be called healthy or safe, which tells us a lot!
FISH CONSUMPTION FOR VITAMIN D: Fish, epecially fatty fish, is always promoted as a good source of vitamin D. This study conducted in the autumn of 2011 in Caucasians living in South-Western Norway (60° north latitude) puts that advice to the test. Sixty-three healthy participants with overweight/obesity were randonly asigned to consume 750g/week of either cod (n=22) or salmon (n=22) as five weekly dinners or were instructed to continue their normal eating habits but avoid fish intake (Control group, n=19) for 8 weeks. Blood samples were collected at baseline and at the end of the intervention. It is generally advised that blood vitamin D levels should be ≥50 nmol/l, but many authorities recommend higher levels of around 100–150 nmol/L. At baseline, 50 of the 63 participants (84%) had blood vitamin D3 levels of >50 nmol/l, but 8 weeks later, this was seen in 31 participants (49%). It was expected that salmon, being a fatty fish, would be sufficient to sustain the vitamin D3 levels throughout autumn. However, although the median daily vitamin D intake was estimated to be 11.9μg in the Salmon group, which was above the recommendation of 10μg vitamin D per day, the vitamin D3 levels decreased in this group albeit to a lesser degree when compared with both the Cod group and the Control group. So the study concludes that eating 750g/week of salmon is insufficient to prevent the seasonal reduction in vitamin D3 levels in the autumn in this group of healthy adults with overweight or obesity living in South-Western Norway.
Eating fatty fish 5 times a week is neither desirable for health nor sustainable for the planet. So we can conclude that the best advice to maintain vitamin D levels for all diet patterns when sun exposure is inadequate is in the form of a supplement. The importance of adequate vitamin D intake has come to the fore during the COVID-19 pandemic because of associations with lower vitamin D levels and worse outcomes. The jury is still out as to whether there is a causal relationship but in the meantime the precautionary principle applies and vitamin D supplementation is considered essential in all ages groups in the UK during the winter months. The UK Government have agreed to make this freely available to elderly and vulnerable groups.
OMEGA-3 AND VITAMIN D SUPPLEMENTS FOR HEALTHY AGING: There is ongoing debate regarding the use of nutritional supplement above that required to maintain nutritional sufficiency. For vegans, there remains uncertainty about the need for long-chain omega-3 (DHA/EPA) supplements from micro-algae, which may be particularly important for healthy aging as the conversion rate of short-chain (ALA) to long-chain decreases. This study examined the role of vitamin D or omega-3 supplements or strength training exercise in 2157 otherwise healthy participants from several European countries with a median age of 74 years. Participants were randomized to 3 years of intervention in 1 of the following 8 groups: 2000 IU/d of vitamin D3, 1 g/d of omega-3s, and a strength-training exercise program (n = 264); vitamin D3 and omega-3s (n = 265); vitamin D3 and exercise (n = 275); vitamin D3 alone (n = 272); omega-3s and exercise (n = 275); omega-3s alone (n = 269); exercise alone (n = 267); or placebo (n = 270). The results showed that after a median of 3 years follow-up there was no significant difference in the outcomes measured; systolic or diastolic blood pressure, nonvertebral fractures, physical performance, infection rates, or cognitive function.
Some points to note. This was a pretty healthy group to start with, so a positive finding would have had to be pretty large to meet significance. The findings regarding strength training exercise are not in line with previous study data and this may be because 83% of participants were already doing moderate to high physical activity at the start of the intervention. Prior meta-analyses have shown a clear benefit in the elderly and so this advice still stands. The participants were healthier than the typical older person and the rates of fracture lower than expected. Also, people not in the vitamin D group were still allowed to take vitamin D supplement inline with current guidelines. The data on vitamin D and omega-3 supplements add to the growing evidence that in healthy people, supra-nutritional doses of vitamins and nutrients very rarely improve health outcomes. Prior data has not confirmed a benefit for omega-3 supplements or from fish for cardiovascular health or brain health. This does not exclude a benefit for those with early stages of chronic illness and it does not provide us with an answer to the role of DHA/EPA supplements in vegans.
MORE EVIDENCE TO SUPPORT GREEN TEA AND COFFEE CONSUMPTION: This study from Japan included 4,923 participants with type 2 diabetes, average age 66 years. Various data were collected, including details about their existing health conditions, frequency of exercise, smoking status, alcohol consumption, sleep duration, body mass index (BMI), blood pressure, and symptoms of depression. Participants also provided details about their diet, including their consumption of coffee and green tea. After a median follow-up of 5.3 years, 309 participants had died. For this analysis, four or more cups of green tea and two or more cups of coffee per day was considered high consumption. The results showed that a combination of higher green tea and coffee consumption significantly reduced all-cause mortality. Both green tea and coffee consumption lowered the risk of death but the effect of the combination was additive. Coffee consumption alone of two or more cups per day was associated with 41% lower chance of dying. Green tea alone four or more cups each day was associated with 40% lower risk of dying. Two to three cups of green tea plus two or more cups of coffee resulted in a 51% lower chance of dying and four or more cups of green tea and two or more cups of coffee a 63% lower risk.
This study adds to many others that confirm green tea and coffee can be a healthy addition to the diet. Both drinks have been associated with a reduced risk of some of our commonest chronic diseases. It’s thought to be due to the high polyphenol content. Despite these positive results, we must not forget that most cases of type 2 diabetes can be prevented through adopting a healthy plant-based diet and lifestyle and if you do have diabetes then an intensive lifestyle intervention, to induce remission should be the aim.
THE STATE OF THE UK FOOD SYSTEM: The UK food system needs to undergo a massive transformation. This report provides information on the current status and a useful baseline for making a positive change. The report highlights the following:
The food sector is the biggest employer, mainly in retail and hospitality. There are 10 large food retailers and Tesco alone holds 21% of the UK market share. Poor working conditions persist, especially for low-skilled labour in the food sector. We mustn’t forget the higher rates of COVID-19 infection in slaughterhouse workers for example, an issue not highlighted in the report. Sales in veg box schemes have increased dramatically with around 500 schemes currently operating.
Diets too rich in fat, sugar, and meat and too low in fruit and vegetables are contributing to obesity and related health problems, especially in deprived households. The UK has the third highest volume sales of ultra-processed foods per capita out of 80 high- and middle-income countries, and the most processed diet of countries in Europe. This contributes to the 63% of UK adults being obese or overweight.
Unsustainable production methods are driving biodiversity loss, soil degradation, pollution, water scarcity and climate change in both the UK and overseas. Land use is dominated by animal and cereal production (e.g. 52% of croppable area in the UK is covered with cereals). The cereal production is mainly for feeding livestock. The UK heavily relies on food imports, particularly the EU. Only 53% of food consumed in 2018 was produced domestically. The biggest imports are of fruits and vegetables but these could be grown in the UK. Issues relating to climate change, COVID-19, and EU- exit highlight the need for greater resilience within the food system.
Women still do most of the cooking at home! Food waste remains a huge problem with most of it occurring in our homes. We throw away 20 millions slices of bread, 4.4 million potatoes, 3.1 million glasses of milk, 2.2 million slices of ham A DAY! The list goes on.
Food poverty is increasing with 4.9 million adults, or 9% of the population affected by food insecurity.
Just by adhering to the Eatwell guide we could reduce the environmental impact of our food system by around 30%
It can be concluded that we urgently need a fair, accessible, affordable plant-based food system that provides nutritious and healthy food for all its citizens and protects those that work in the food industry. Lets hope this report is the starting point for change.
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