A review of the week’s plant-based nutrition news 1st August 2021

This week I cover plant-based diets and prostate health, the hazards of eating red meat, foods important for gut health, Pharma influence on healthcare and yet another stark warning from scientists about the climate emergency.

HEALTHY PLANT-BASED DIET AND PROSTATE HEALTH. Very excited to read these results. Prostate specific antigen (PSA) levels are a marker of prostate health in men. Elevated levels can indicate the presence of prostate cancer. Back in 2005, Dean Ornish, MD published a paper demonstrating that a plant-based diet with other healthy lifestyle interventions could slow the progression of early stages of prostate cancer. He subsequently showed that his lifestyle approach could increase telomere length and favourably alter gene expression in prostate cancer biopsies.

This new study examines the impact of diet quality on PSA levels in men participating in the US National Health and Nutrition Examination Survey. The study analysed dietary data using the plant-based diet index, which gives positive marks for healthy plant foods such as fruits, vegetables, whole grains, beans, nuts and seeds and negative marks for all animal foods and unhealthy plant foods, such as refined grains, sugar-sweetened beverages and processed foods.

1399 men with a median age of 54 years were included in the study. The results showed that higher adherence to a healthy plant-based diet was significantly associated with a lower probability of having an elevated PSA. That is, consuming more plants is associated with lower PSA levels.

Accepting the limitations of this small, cross-sectional study, which can not prove cause and effect, these results are pretty encouraging. They allow us to provide men with actionable changes to make to the diet to promote prostate health. Previous studies have shown certain foods are particularly good for prostate health including lycopene-rich fruits and vegetables such as tomatoes, soya foods, cruciferous vegetables, polyphenol-rich foods including tea and coffee and flaxseeds. One of the foods to avoid for prostate cancer prevention is dairy as it has consistently been associated with an increased risk. Check out my article on diet and prostate cancer.

PROCESSED AND UNPROCESSED RED MEAT INCREASES THE RISK OF ISCHAEMIC HEART DISEASE: Heart disease is the leading cause of death worldwide. Yet we know that 80% of heart disease could be wiped out by addressing diet and lifestyle habits and preventing risk factors such as obesity, high blood pressure and type 2 diabetes. A Western-style diet pattern, high in animal and processed foods, is the worst type of diet for heart health. We have known for decades that the consumption of processed and unprocessed red meat increases the risk of heart disease, although some researchers have tried to muddy the science by suggesting its impact on heart health is not significant enough to warrant public health interventions.

This systematic review and meta-analysis puts the final nail in the coffin of red meat consumption. The analysis included 13 cohort studies and 1,437,989 individuals and clearly demonstrates that the consumption of red meat and processed meat significantly increases the risk of developing ischaemic heart disease (IHD). For each 50 g/day higher consumption of unprocessed red meat (beef, lamb, pork) there was a 9% increased risk of ischaemic heart disease and for each 50g/day of processed meat (bacon, ham, sausage) an increase of 18%.

The authors conclude: “This supports public health recommendations to reduce the consumption of unprocessed red and processed meat intake for the prevention of IHD”.

We already know from previous studies that for each 50g portion of processed meat (the size of one hot dog) consumed daily there is an 18% increased risk of colorectal cancer and for each 100g portion of unprocessed red meat consumed a 17% increased risk. The WHO has classified processed meat as a definite carcinogen (in the same category as smoking and asbestos) and red meat as a probable carcinogen, associated with the development of colorectal cancer. Processed and red meat consumption has also been associated with other cancers such as breast, pancreatic and prostate cancers, and to increased cancer mortality.

Of note, the current study does not find an association of poultry consumption with heart disease. This does not give a green light to eating chicken in my view. There are so many better choices we can make that actually reduce the risk of heart disease. Vegetarian and healthy plant-based diets (that exclude poultry) significantly reduce the risk of heart disease. ‘White meat’ including poultry has shown to elevate LDL-cholesterol levels and increase the risk of hypertension. Swapping out poultry and replacing with plant sources of protein, such as beans and nuts, significantly reduces the risk of death from all-causes including cardiovascular disease.

Back to the study in question, there is no doubt that red and processed meat consumption causes more harm to health than benefit. When environmental consequences of its production are taken into account, there is no place for these ‘foods’ in our modern diet. That’s why we are calling for all health professionals to support patients and citizens to remove all red meat from the diet.

DIET, GUT MICROBIOME AND IMMUNE HEALTH: We know that the health of our gut microbiome plays a major role in the functioning of the immune system throughout the body. Diet choices are a major determinant of gut health and hence immune health. The health of the gut microbiome has also been shown to be a determinant of COVID-19 severity. The main foods that promote gut health are fibre, polyphenol-rich plant foods and fermented foods that contain live bacteria.

In this clinical trial, 36 healthy adults were randomly assigned to a 10-week diet that included either fermented or high-fibre foods. Blood and stool samples collected before the trial, at the end of the 10 weeks and 4 weeks after the end of the study once participants had resumed their usual diet.

The results showed that the two diets resulted in different effects on the gut microbiome and the immune system with a greater benefit from consuming fermented foods, which was shown to enhance the diversity of gut microbes and decreases signs of inflammation. The participants increased consumption of fermented foods including yogurt, kefir, fermented cottage cheese, kimchi, other fermented vegetables, vegetable brine drinks, and kombucha tea, to 6 servings a day. This led to an increase in overall microbial diversity, with greater effects from larger servings. In addition, the function of certain immune cells was altered in the fermented-food group and levels of 19 inflammatory proteins measured in blood samples also decreased. This is quite an impressive result for such a short term intervention.

In contrast, the fibre-rich diet group who increased their fibre intake from 21g/day to 45g/day by eating more legumes, seeds, whole grains, nuts, vegetables and fruits showed less of an effect on the gut microbiome in which microbial diversity remained stable. In addition, the greater fibre intake led to more carbohydrates in stool samples, suggesting incomplete fibre degradation by gut microbes. The authors hypothesise based on further stool testing that this may be a consequence of the typical microbiome of people living in the industrialised world, which is depleted of fibre-degrading microbes. Thus, it might be that a longer period of time is needed for the gut microbiome to adapt to a fibre-rich diet.

The take home message is that changes to the diet can result in changes to the health of the gut microbiome, which then influence the functioning of the immune system. Adding fermented foods to the diet may be a good way of maintaining gut and immune health and there are many plant-based options for fermented foods. Despite the less pronounced changes with increased fibre consumption, we should not underestimate the long-term benefits of a fibre-rich diet. These include reduced risk of cardiovascular disease, cancer, type 2 diabetes, overweight and obesity and more.

BIG PHARMA FUNDING OF UK GOVERNMENT GROUPS: Two articles in the PLOS journal caught my attention this week. The first is a perspective article by 5 research scientists calling into question the research and clinical priorities of the global healthcare industry. They remind us that although we are living longer we are living longer in ill health with more than 65% of those aged over 65 years having at least 2 underlying chronic conditions. In fact, I in 3 middle-aged people in the UK have 2 or more underlying chronic conditions. Yet 80% of cardiovascular disease and 40% of cancers, our two main causes of death and disability, could be prevented with diet and lifestyle interventions. These preventative strategies are important from the moment of conception. Despite this, the medical community and Governments in most countries spend the majority of healthcare funding to deal with established illness rather than on preventing it in the first place. In the UK, only 5% of the healthcare budget is spent on prevention. The authors argue that the emphasis on pharmaceutical and technological solutions to ‘sick care’ is no longer sustainable, fair or equitable for our global society. They highlight the negative impact of healthcare practices on environmental and ecological health. In addition, they discuss the negative impact of animal agriculture on human health and planetary health by sustaining the consumption of unhealthy meat-based diets, contributing to land, water and air pollution, driving antibiotic resistance and increasing the risk of new infections with pandemic potential.

The authors eloquently summarised the sad situation we are in ‘Waiting for millions of people, who eat unhealthy food and engage in harmful lifestyles, to end up in outpatient clinics or hospitals with symptoms of chronic diseases is unethical and financially and environmentally unsustainable’. Disease prevention needs to take front and centre stage of all healthcare systems through a focus on education and interventions at all life stages.

With this poignant perspective in mind, it is very sad to read the results of the paper highlighted above. In the UK, All-Party Parliamentary Groups (APPGs) are informal cross-party groups revolving around a particular topic run by and for Members of the UK’s Houses of Commons and Lords. They facilitate engagement between parliamentarians and external organisations, disseminate knowledge, and generate debate through meetings, publications, and events. The paper examined sources of funding for 146 health-related APPGs. Sixteen of 146 (11%) health-related APPGs had conflicts of interest indicated by reporting payments from thirty-five pharmaceutical companies worth £1,211,345.81. Two APPGs (Health and Cancer) received more than half of the total value provided by drug companies. The study analysis also suggested that this funding may influence the output from these groups as these pharma companies contribute to inquiries and have their interests reflected in reports.

Until government and healthcare is free of industry influence, we will continue to have a healthcare agenda driven by financial interests rather than centring the requirements of society.

SCIENTIST WARN US AGAIN OF A CLIMATE EMERGENCY: 29th July 2021 marked Earth Overshoot Day ‘the date when humanity’s demand for ecological resources and services in a given year exceeds what Earth can regenerate in that year’. At the same time, this study which is tracking the planet’s vital signs has found that the global climate crisis is getting worse and either approaching or exceeding key tipping points. Out of the 31 variables tracked, the researchers found that 18 are at new all-time record lows or highs (all negative changes). To focus in on a few of the relevant findings, the study reports that ruminant animals, which are a significant source of greenhouse gas emissions, now number more that 4 billion and their total mass is more than that of all humans and wild-life combined. The rate of forest loss in the Brazilian Amazon increased in both 2019 and 2020 reaching a 12-year high of 1.11 million hectares deforested in 2020. Last week I highlighted that the Amazon now emits more carbon than it sequesters. Atmospheric concentrations of 3 greenhouse gases, carbon dioxide, methane, and nitrous oxide, are at all time highs. Ocean acidification is also near an all-time record and along with rising ocean temperatures continues to threaten ocean life.

In 2019, William Ripple and colleagues warned of ‘untold suffering and declared a climate emergency together with more than 11,000 scientist signatories from 153 countries’. Two years later, he and his colleagues ‘reaffirm the climate emergency declaration and again call for transformative change, which is needed now more than ever to protect life on Earth and remain within as many planetary boundaries as possible’. It truly feels like time is running out to change the catastrophic trajectory of our planet.

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