A review of the week’s plant-based nutrition news 29th August 2021
This week I focus in on cardiovascular disease with papers that cover the impact of healthy lifestyle habits, benefits of eating nuts and polyphenol-rich foods. I also include a reminder of the urgent need to address climate health.
LIFESTYLE INTERVENTIONS IN CARDIOVASCULAR DISEASE (CVD): We have known for some time that the majority of CVD is preventable. Despite this knowledge, prevalence of CVD continues to rise due to a rise in the presence of risk factors, including hypertension, type 2 diabetes, obesity and high cholesterol. It’s great to see this topic being discussed by the cardiology community in order to empower front line clinicians to incorporate this knowledge into clinical practice.
The paper reviews the strong evidence supporting healthy lifestyle habits for prevention and treatment of CVD. First and foremost, the benefits of eating a diet predominantly composed of whole plant foods (fruits, vegetables, whole grains, nuts and seeds), whilst eliminating or greatly reducing the consumption of animals-derived foods and processed foods. A low-carbohydrate diet is warned against due to the elimination of some of our healthiest carbohydrate-rich foods, the association with elevated LDL-cholesterol and longer term associations with increased risk of CVD, cancer and negative impact on mortality. Intermittent fasting is reviewed and the authors conclude that although initial results are promising, we don’t currently have enough data to recommend this for management of CVD.
Individual nutrients are reviewed. The authors acknowledge that there is very little data supporting the use of omega-3 supplements for primary prevention of CVD. However, for those with established CVD, there may be a role for high doses of DHA/EPA (around 1g). A highly purified form of EPA in patients with high triglycerides may be particularly useful for preventing further CVD events. Plant sterols are a useful addition to the diet for reducing cholesterol levels and can be obtained from vegetables, fruit, wheat germ, beans, sunflower seeds, and various oils. The National Lipid Association advocates 2g/d of plant sterols with expected reduction in LDL-cholesterol of 5–10%. Herbs and spices are fully of powerful nutrients. Cinnamon and turmeric consumption in particular is associated with a decrease in fasting blood glucose, triglycerides, and LDL-cholesterol. Nitrite/nitrate rich plant foods significantly decrease resting blood pressure, improve endothelial function, reduce arterial stiffness, and reduce platelet aggregation. Last but not least, fibre consumption is hugely beneficial to CV health, with fibre from whole plant foods better for health than consuming foods supplemented with fibre.
The aspects of lifestyle that are less debated are that regular physical activity is hugely important for primary and secondary prevention of CVD, with both aerobic and resistance exercise being important. Exercise reduces body fat, fasting glucose, blood cholesterol and blood pressure and improves insulin sensitivity and reduces inflammation. The authors emphasise the importance of stress reduction through techniques such as mindfulness, transcendental meditation, optimism, yoga, relationships and connectedness, including sharing your home with a companion animal.
The authors acknowledge the difficulty with behaviour modification and that an individualised approach is needed with multiple resources required to support patients. They also acknowledge the need for public policy initiatives and supporting all communities regardless of financial means to adopt healthy lifestyles. They conclude ‘it is paramount that we increase education of the physician and other clinicians in these lifestyle interventions to reduce CVD risk and improve CVD health globally’.
We know that knowledge and information is not enough to support our patients to make behaviour changes. This is an excellent review article on how to support patients. As clinicians we have to change from an expert approach to the coach approach.
PECANS LOWER CHOLESTEROL: One of the most important risk factors for CVD is blood cholesterol. In fact, it is the most important risk factor for atherosclerosis. A recent editorial titled ‘How to live to 100 before developing clinical’ focuses entirely on how to lower blood cholesterol level. The lower the LDL-cholesterol the better. We already know that people who avoid all animal foods have the lowest blood cholesterol of any diet pattern. However, there are certain foods that can be incorporated into a plant-based diet to further lower cholesterol levels.
The current randomised study examined the impact of pecan consumption on blood cholesterol levels in 56 overweight adults with a high blood cholesterol. The 3 groups were asked to follow different diet interventions for 8 weeks. The control group (n=18) were instructed to avoid all forms of nuts and to consume ≤64 g of nut butter/week. The intervention groups was provided with 68g/day portion of pecans to consume as part of their usual diet with no additional diet instructions (n=16) or were instructed to substitute the 475 kcal provided by the 68 g of pecans for foods habitually consumed in their usual diet (n=18). Blood test for cholesterol, triglycerides and glucose were preformed before and after the intervention, including fasting and post meal levels.
The results showed significant reductions in total and LDL-cholesterol in the pecan groups with an average drop of 5% in total cholesterol and between 6% and 9% in LDL-cholesterol in participants who consumed pecans. Both fasting and post meal levels were improved. Similar benefits in cholesterol levels were seen whether participants added pecans to the diet or substituted other foods in the diet for pecans. These findings are clinically meaningful because a 1.0% reduction in LDL cholesterol is associated with a 1.2–2.0% reduction in the risk of coronary artery disease. Post-meal triglycerides were reduced in the group that added pecans. Post-meal glucose was lowered in the group that substituted pecans.
The reason why pecans are effective at improving blood lipid levels could be explained by the high fibre content, the mono- and polyunsaturated fats and polyphenol content of pecans.
The authors conclude ‘The results of this study are clinically meaningful because the magnitude of reduction in LDL-cholesterol in the pecan groups (6.4–9.5%) could correspond to a 6.5–11.4% reduction in the risk for coronary artery disease’.
We have known for a while that nuts are an excellent addition to the diet and have cholesterol lowering effects. In fact the Portfolio diet, designed to lower cholesterol, incorporates 45g of nuts per day. Just four brazil nuts a month can also have a significantly impact on cholesterol levels.
POLYPHENOLS, GUT MICROBIOME AND BLOOD PRESSURE: Dietary flavonoids, a large group of plant-derived polyphenolic compounds, are commonly found in fruits, vegetables, tea, chocolate, and red wine. Last week I wrote about the association of lignan consumption, a polyphenol compound, with lower risk of coronary heart disease. Polyphenols are one of the dietary components that positively impact the health of the gut microbiome and it is thought that this then influences disease outcomes.
The current study included 904 participants from a German-based population cohort who had undergone dietary assessment, biometric measurements and blood and stool analysis. The results showed that higher consumption of flavonoids was associated with a lower systolic blood pressure, but not diastolic blood pressure. The top foods associated with this positive impact were berries, red wine, apples and pears. For example, participants consuming the higher amounts of berries (equivalent to 1.6 portions per day), red wine (equivalent to 2.8 glasses [250 mL] per week), and apples/pears (equivalent to 1.6 portions per day) had up to 4mmHg lower systolic blood pressure. These foods were associated with beneficial changes in the gut microbiome, including increased diversity, lower abundance of pathogenic bacteria and increased abundance of beneficial species. Overall, the authors conclude that up to 15.2% of the association between flavonoid-rich foods and blood pressure could be explained by changes in the gut microbiome.
The authors report that it has been estimated that reducing the population average BP by 5 mmHg could save 45,000 quality-adjusted life years and save £850m on related health and social care costs in Germany. The amount required of these foods are easily achievable with clinically meaningful impacts.
I do once again caution against relying on red wine for polyphenol intake and gut health as it is the compounds in the grapes that are of benefit, not the alcohol, and thus it is preferable to avoid the negative impacts of the alcohol consumption on health.
PLANETARY HEALTH ALLIANCE: Plant-Based Health Professionals UK is delighted to be the newest member of the Planetary Health Alliance, a consortium of over 240 universities, non-governmental organizations, research institutes, and government entities from around the world committed to understanding and addressing global environmental change and its health impacts. Our acceptance as a member organisation gives us hope that there is global recognition that a transition to a plant-based food system is one of the required solutions.
Given the state of the global climate emergency, large scale changes are required. On an individual level, diet change can be very impactful. Removing all red meat and dairy from the diet and replacing these foods with healthy plant foods has the greatest impact on personal and planetary health.
A recent study published in Nature Food evaluated more than 5,800 foods, ranking them by their nutritional disease burden to humans and their impact on the environment. Researchers classified foods into three colour zones: green, yellow and red, based on their combined nutritional and environmental impacts. The green zone represents foods that are recommended to increase in the diet that are both nutritionally beneficial and have low environmental impacts. Foods in this zone are predominantly nuts, fruits, field-grown vegetables, legumes, whole grains and some seafood. The red zone includes foods that have either considerable nutritional or environmental impacts and should be reduced or avoided in the diet. Nutritional impacts were primarily driven by processed meats, and climate and most other environmental impacts driven by beef and pork, lamb and processed meats.
The analysis found that substituting 10% of daily caloric intake from beef and processed meats for a mixture of fruits, vegetables, nuts, legumes and select seafood could reduce your dietary carbon footprint by one-third and allow people to gain 48 minutes of healthy life per day.
We can’t wait for the release of the new documentary Eating Our Way To Extinction, which features Plant-Based Health Professionals UK team members! I hope this film will convince people that we have to change now. If not now, when? There is no time to lose.