A review of the week’s plant-based nutrition news 27th March 2022

This week is dedicated to prevention of cardiovascular disease, which remains the top cause of death globally. It is estimated that by addressing diet, lifestyle and psychosocial factors we could prevent or delay 90% of these conditions.

Cardiovascular disease (CVD) is the general term given to a group of disorders that affect the heart and blood vessels. The INTERHEART and the INTERSTROKE studies demonstrated that modifiable lifestyle and psychosocial factors were responsible for 90% of the risk of developing a heart attack or stroke. Therefore, our approach to reducing the incidence and mortality from these conditions should focus on addressing these risk factors.

OPTIMAL NUTRITION FOR CARDIOVASCULAR HEALTH: This new practice statement from the American Society for Preventive Cardiology brings us up to date with the evidence on the optimal nutritional approach for prevention of atherosclerotic cardiovascular disease.

The evidence really hasn’t change for decades, but has strengthened through the availability of additional studies. The recommendations are that health professionals should recommend a plant-predominant diet centred around foods that promote health and prevent atherosclerosis i.e. fruit, vegetables, whole grains, legumes, nuts, seeds and fatty fish. The recommendations can be met by following a Mediterranean, DASH (dietary approaches to stop hypertension), healthy vegetarian or exclusively plant-based diet. The main difference between these diet patterns is the amount of animal products included, with the Mediterranean and DASH diet patterns including fish, lean meats and low fat dairy. They share in common the minimisation of processed meats, refined carbohydrates and sugar-sweetened beverages, limiting the amount of dietary cholesterol and sodium, replacing saturated fat with monounsaturated and polyunsaturated fats, and avoiding trans fats.

The guidelines do continue to recommend the consumption of fatty fish without addressing the environmental sustainability of this approach. The main benefits of consuming fish appear to be mainly a substitution effect (if you are eating fish you are generally eating less of other types of animal flesh) and the long-chain omega-3 content (DHA/EPA). Algae-derived omega-3, the primary source for fish, has a similar effect on blood omega-3 levels as the consumption of fish and plant-exclusive/healthy vegan diets have significant benefits for cardiovascular health. The additional benefit of fish is yet to be established.

The guidelines warn against an animal-based low-carbohydrate or ketogenic diet given the adverse impact on long term cardiovascular health. In theory, a low-carbohydrate plant-based approach may be beneficial but there are no long-term studies with hard clinical outcomes. In addition, there is no strong evidence that intermittent fasting has additional benefits to calorie restricted diets for weight loss or cardiometabolic health.

I am pleased to see paediatric nutrition included and the negative impact that socioeconomic disparities and racism can have on access to healthy nutrition and consequent health outcomes. The document is open access and well worth reading.

OUR GENES ARE NOT OUR DESTINY: Another reminder that you can positively influence your risk of heart disease through healthy lifestyle behaviours regardless of your genetic risk. This study examined the lifetime risk of coronary heart disease (CHD) and the years lived free of CHD, based on a polygenic risk score and adherence to the American Heart Association’s Life’s Simple 7 (LS7) recommendations in both White (n=8372) and Black (2314) participants. The polygenic risk score included more than 6 million genetic variants and was used to categorise participants into low, intermediate and high risk of CHD. The LS7 includes 7 cardiovascular health factors; smoking status, body weight, total cholesterol, blood glucose, physical activity, and diet. A healthy diet was evaluated on the basis of 5 components: if an individual consumed ≥4.5 cups/day of fruits and vegetables, ≥2 3.5oz servings/week of fish, 3 1oz equivalent servings/day of fibre-rich whole grains, and restricted their diet to <1500mg/day of sodium and ≤450kcal/week of sugar-sweetened beverages, they were considered to meet all 5 criteria for an ideal healthy diet.

Overall, the results demonstrated that 1 in 3 individuals with high genetic risk and 1 in 2 individuals with a poor lifestyle score will experience a cardiac event in their lifetime. White participants with a high genetic risk and unhealthy lifestyle lived 16 years fewer without heart disease. In Black participants there was less of an impact of the high risk genetic score suggesting lifestyle factors may be more important. The impact of a high genetic risk was shown to be reduced by up to 50% through adherence to healthy lifestyle recommendations. On average, individuals with a high polygenic risk who maintained a poor lifestyle experienced a CHD event 20 years earlier than those with a same genetic risk profile but adhered to an ideal lifestyle. Lifestyle had a larger impact on the lifetime risk of CHD than genetic information.

RED MEAT AND RISK OF ALL-CAUSE AND CARDIOVASCULAR MORTALITY: Despite the strength and consistency of evidence, reputable scientists continue to deny the risks associated with red meat consumption based on a flawed assessment of the data. Here I highlight yet another study which included 180,642 participants followed for a median of 8.6 years that demonstrates a negative impact of unprocessed red meat consumption on health outcomes. The results showed that compared to those consuming red meat < 1.5 times/week, participants consuming red meat ≥ 3.0 times/week had a 20%, 53% and 101% increased risk of dying from CVD, heart disease and stroke. For everyone 1-serving/day increase of red meat intake there was a 7%, 15% and 18% higher risk of CVD, CHD, and stroke mortality. The negative impact of red meat consumption was worse in those who smoked and who ate the least vegetables. These associations were independent of and not modified by genetic factors. Substitution analysis showed that replacing red meat with poultry or cereals significantly reduced the excess risk of death.

The authors conclude “Our study provides further evidence that replacement of red meat with consumption of foods rich in healthier protein sources is related to a lower risk of mortality,”.

MORE DATA SUPPORTING A HEALTHY PLANT-BASED DIET: I talk about the plant-based dietary index a lot. Here is a reminder of what it is. In this study from Greece, the impact of a plant-based diet was assessed in 2,020 men and women followed for a median of 8.6 years. Higher adherence to a healthy plant-based diet was associated with up to a 68% reduction in risk of developing CVD. In contrast, an unhealthy plant-based diet increased the risk by 34%. The benefits of healthy plant foods was less evident in those consuming low amounts of animal foods, leading the authors to suggest that a more balanced and moderate approach to nutrition advice may be ‘less meat’ and more ‘healthy plant foods’.

Check out my article on how and why a healthy plant-based diet prevents cardiovascular disease.

BENEFITS OF SOYA CONSUMPTION: Soya has to be one of the most misunderstood foods in a plant-based diet. Yet the data are overwhelmingly supportive of the benefits for all aspects of health. Much of the observational data on the benefits of soya consumption come from SE Asian population who consume a lot more than Western populations. This new analysis from the 4C study in China, included 97,390 participants with a average age of 56 years. During the 3.2 years of follow up there were 2523 CVD events (hospitalised or treated heart failure, non-fatal stroke, non-fatal myocardial infarction, and cardiovascular mortality) and 1473 deaths. Higher consumption of soya >60g per day when compared with <15g/day was associated with a 17% lower risk of all-cause mortality, 14% lower risk of cardiovascular disease, 19% lower risk of stroke, and a non-significant 23% reduction in risk of cardiovascular disease mortality. No clear association was observed for non-fatal myocardial infarction or heart failure.

These data are consistent with prior results from observational and intervention studies. Soya is a unique legume and a valuable source of nutrients including high-quality protein, polyunsaturated fatty acids, carbohydrates, fibre and a number of phytochemicals such as isoflavones, phytosterols, and lecithin. We have known for a long while that soya protein is associated with a lowering of blood total and LDL-cholesterol levels and and hence forms one of the 4 components of the dietary portfolio, with established benefits for cardiovascular health.

For more information on soya, check out this article from Dr Nitu Bajekal and our factsheet on tofu for children by Dr Miriam Martinez-Biarge here. If you are allergic to soya, don’t worry, you can still have a very healthy plant-based diet. Check out these top tips by nutritionist Rohini Bajekal.

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