A review of the week’s plant-based nutrition news March 22nd 2020

For those of you who want to briefly take your minds off the current pandemic, I will try and continue providing a summary of some important papers on plant-based nutrition in the coming weeks.

THE SUSTAINABLE DIET INDEX AND RISK OF CANCER AND CARDIOVASCULAR DISEASE (CVD): There are a number of ways of classifying diet patterns when analysing food frequency questionaires. One newly described categorisation is the Sustainable Diet Index (SDI), which takes into account not only foods that are healthy and nutrient rich for humans, but that are also sustainable for the planet. The Food and Agricultural Organization define sustainable diets as those are; ‘protective and respectful of biodiversity and ecosystems, culturally acceptable, accessible, economically fair, and affordable; nutritionally adequate, safe, and healthy; while optimizing natural and human resources’. Of course, the production of plant-based foods have far less of an environmental impact than animal-derived foods. In general a higher SDI score is associated with lower consumption of animal food (meat and processed meat, dairy products and milk, seafood and fish), alcoholic beverages, fruit juices and sweet foods and higher consumption of fruits, vegetables, whole grains and legumes.

New analysis from the NutriNet-Sante study, which included 25592 participants followed for 3.8 years, documenting 483 cases of cancer and 158 cases of CVD, suggests more sustainable dietary patterns with less meat and dairy products and more whole grains, legumes and nuts, fruits and vegetables and soya products are associated with a lower risk of both cancer and CVD. There was a 44% reduction in overall cancer incidence, 59% reduction in breast cancer risk and a non-significant 26% reduction in CVD risk. The results are consistent with a previous analysis which found increased cancer risk overall and breast cancer risk with intake of red meat in the same study. The current study demonstrates that a diet that prevents environmental destruction can also support human health and reduce the risk of the most common causes of death globally.

IMPROVED SURVIVAL AFTER BREAST CANCER WITH A HEALTHY DIET: To continue the theme of cancer, this study reports findings from the Women’s Health Initiative trial, one of the largest and most expensive nutrition interventions of all times. 48,835 postmenopausal women, ages 50–79 years, with no prior breast cancer, and a dietary fat intake of >/= 32% of energy were randomly assigned at 40 US centres to a usual diet (60%) or dietary intervention group (40%). The goals of the diet intervention were to reduce fat intake to 20% of energy and increase vegetable, fruit, and whole grain intake. Unfortunately, the intervention group did not meet the target of <20% fat intake with a median intake of 24% of calories from fat. Nonetheless, this was lower than the control group with lower intakes of saturated fat and a significant increase in consumption of whole grains, fruits and vegetables.

The study reports almost 20 years of follow-up and found that those women who developed breast cancer and were in the intervention group, had a significantly reduced risk of death (15% reduction in risk) following the diagnosis. The risk of dying of breast cancer itself was reduced by 21%.

The study concludes ‘adoption of a low-fat dietary pattern that included increased vegetable, fruit, and grain consumption is demonstrably achievable by many postmenopausal women. Such a dietary pattern may reduce the risk of death as a result of breast cancer in postmenopausal women’. The results add to a growing body of evidence that lifestyle interventions, even after a diagnosis of cancer can have a positive impact on outcomes.

LIFESTYLE TRUMPS GENETIC RISK IN TYPE 2 DIABETES: We often blame our genes as a reason for developing a chronic disease when data actually show that healthy lifestyles can mitigate the risk of adverse genetic risk. This study highlights this fact very well. The aim of this study was to determine whether genetic risk and adherence to a healthy lifestyle contribute independently to the risk of developing type 2 diabetes. Almost 500,000 participants from 2 prospective Chinese cohort studies were included. The lifestyle score included BMI, alcohol intake, smoking, physical activities, and diets and is shown in the table below. The lower the score the more healthy the lifestyle. Note that all meat was categorised together and contributed to a less healthy lifestyle in the scoring system, whilst all plant foods were deemed healthy. A genetic score was also constructed using almost 50 loci deemed to be associated with an increase risk.

Table: Components of the healthy lifestyle score.

The study found that a healthy lifestyle was associated with a substantially lower risk of type 2 diabetes than an unhealthy lifestyle, regardless of genetic risk. In those at a high genetic risk, the risk of type 2 diabetes was 57% lower among participants with a healthy lifestyle than among those with an unhealthy lifestyle. In those with a high genetic risk, the 10-y incidence of type 2 diabetes was 7.11% in those with an unhealthy lifestyle vs. 2.45% in those with a healthy lifestyle. So once again, lifestyle trumps the impact of genes.

DIET AND THE RISK OF OSTEOARTHRITIS: We seem to have accepted that osteoarthritisn (OA) is an inevitable consequence of aging and affects approximately 10% of men and 18% of women worldwide. The only conventional treatments are pain killers and joint replacements. Of course, the main risk factor remains an elevated body mass index. Yet, joint inflammation plays a role in the pathogenesis and hence an anti-inflammatory diet may also impact its development and progression.

This study reports finding from the The Osteoarthritis Initiative, a longitudinal study that included 4796 individuals aged 45–79 y in 2004. All participants had either established symptomatic knee OA or significant risk factors for the development of knee OA. All participants completed an assessment of dietary intake at baseline. Two dietary patterns were defined (Table below); the prudent pattern, which reflected high intakes of vegetables, fruit, fish, whole grains, and legumes; the Western pattern, which was characterized by high intakes of red and/or processed meats, refined grains, and french fries.

During the 48 months of follow-up, the Western pattern was associated with increased radiographic and symptomatic progression of knee OA, while adherence to a Prudent dietary pattern was associated with a decreased risk. After adjustment for body weight the association still remained with a Western diet increasing the radiographic risk of progression by 22% and the Prudent diet decreasing the risk by 19%. The Western diet increased the symptomatic risk of progression by 26% and the Prudent diet reduced the risk by 29%.

This study adds to evidence from a small randomised study of a whole food plant-based diet in patients with OA. The study found that the diet intervention improved self-reported symptoms and function in the participants.

A CALL TO ACTION FROM THE UK: This paper from scientists and health professionals in the UK urges us to reduce meat intake and increase the consumption of whole plant foods for the health of humans and the planet. It urges a top down approach and asks health professionals to play its part in this transition; ‘Medical professions in developed nations are becoming more aware of the joint human and environmental health consequences of meatrich diets, though additional sustainable dietary training for General Practitioners (who are the first point of call for most patients seeking medical help) is advised. It is imperative that, as part of the prevention and treatment of lifestyle-related diseases, patients are educated and appropriately referred tomultidisciplinary prescribers of optimal nutrition and other determinants of wellbeing. Training of this ‘One Health’ approach should be expanded for all medical professionals who advise on health and diets’.

We have put together a summary of this paper in a free download that can be shared with friends, family and patients, to explain the necessity of reducing meat consumption and how this might be acheived.

PLANT-BASED CHALLENGE IN THE SOUTH-WEST OF ENGLAND: Dr Alan Desmond gives an exclusive interview to Plant Based News and reports the initial outcome of his plant-based intervention in the South West of England. In collaboration with the Happy Pear, Dr Desmond recruited 100 health professionals in January 2020 to switch to a plant-based diet for a month. The results are remarkable, with significant reductions in body weight and cholesterol in those participants that started the challenge in an unhealthy range. Read the full story here.

STAYING HEALTHY DURING THE COVOD-19 PANDEMIC: If you are looking for information on staying healthy during the current pandemic, then there are two webinars you can sign up to. The one highlighted above is free. There is also a paid webinar by Dr Michael Greger.

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