Review of the plant-based nutrition and lifestyle medicine news September 2024

This month I highlight new guidance on hypertension, lifestyle medicine benefits for COVID-19 and cancer, impact of diet patterns on risk of mortality and more discourse around ultra-processed foods.

This month the Independent review of the NHS in England was published. The report, led by Lord Darzi, describes the NHS as being in a ‘critical condition’. We are suffering with a huge burden of preventable illness, such that the NHS can no longer cope. Some of the key themes and recommendations align closely with our work at Plant-Based Health Professionals UK. That is, both sustainable and preventative healthcare need to be prioritised to regain control. Plant-based diets and lifestyle medicine are key to improving individual health but are also essential for sustaining planetary health. The four pillars of sustainable healthcare, prevention, patient empowerment, lower carbon alternatives and lean pathways, are all achieved by prioritising a food and lifestyle medicine approach. The key question now is what will implementation look like.

New hypertension guidelines

Hypertension is a leading risk factor globally for chronic disease. Specifically increasing the risk for conditions such as heart disease, stroke and kidney disease. Yet hypertension is largely preventable and if already established can be managed by addressing lifestyle factors. All six pillars of lifestyle medicine are important for maintaining a normal blood pressure along with a healthy body weight.

This new guidance on the management of blood pressure and hypertension from the European Society of Cardiology is well worth reading. It emphasises lifestyle interventions first and foremost along side pharmaceutical interventions. I love that the authors state the following ‘Given the salutary benefits of healthy lifestyle on a range of outcomes that extend well beyond BP-lowering effects, including broad mental and physical health benefits, we do not require lifestyle interventions to have randomised controlled evidence for efficacy in reducing CVD events through BP lowering to achieve a Class I recommendation’. Often we distract ourselves from common sense approaches by rigidly waiting for the perfect study.

The lifestyle recommendations include regular physical activity (aerobic exercise and isometric and dynamic resistance exercise), optimising weight, increasing dietary potassium intake and reducing sodium intake, reducing alcohol consumption (I would say its best to avoid alcohol) and not smoking. The dietary recommendations are for adopting a DASH or Mediterranean-style diet pattern. These diet patterns have been most thoroughly investigated within the setting of clinical studies. We know that the beneficial aspects of these diets are the emphasis on whole plant foods, the consumption of which are associated with benefits for blood pressure. The current guideline refers readers to the 2021 ESC Guidelines on cardiovascular disease prevention in clinical practice for further dietary guidance. This earlier guideline recommends adopting ‘a more plant- and less animal-based food pattern’. We know hat plant-based diets, especially when free of all animal foods, have a significantly beneficial effect on blood pressure. The evidence for this is nicely summarised in this recent review article. ‘The DASH diet was designed around the vegetarian diet, but with animal-sourced foods added to make it ‘more acceptable’. Interestingly, some studies have shown that consumption of any type of animal flesh is associated with a significant increase in blood pressure. The current guidelines also mentions that coffee consumption does not impact blood pressure but warns against the consumption of sugar-sweetened beverages given its adverse impact on cardiovascular disease outcomes.

Please check out our factsheet on hypertension which aligns with the current guidance and is designed to be used by individuals and within clinical settings.

Modifiable lifestyle factors and the risk of post-COVID-19 multisystem sequelae, hospitalization, and death

I wrote a lot about diet and lifestyle approaches during the COVID-19 pandemic as it was clear from studies that people with healthier lifestyles and less chronic conditions had a better outcome from the infection. You can find my articles here. Scroll down for all the scientific evidence as it emerged over the two year period. Now, over four years from the start of the pandemic, the scientific evidence once again highlights the importance of lifestyle factors for predicting the severity of COVID-19.

This study assessed the impact of lifestyle factors on infection severity in 68,896 participants of the UK biobank study who had a positive SARS-CoV-2 test result between March 1, 2020 and March 1, 2022. Ten prespecified potentially modifiable lifestyle factors were assessed, including smoking, alcohol consumption, body mass index (BMI), physical activity, sedentary time, sleep duration, intake of fruit and vegetable, intake of oily fish, intake of red meat, and intake of processed meat. A healthy diet was deemed that which was consistent with UK healthcare and Government guidance (i.e. similar to the Eatwell guide).

The results showed that a favourable lifestyle score was associated with a lower risk of hospitalisation (22% reduction) and death (41% reduction). In addition, adherence to healthy lifestyle habits resulted in a lower risk of multi-organ sequelae of infection, aka long-COVID (36% reduction). These beneficial impacts occurred during both the acute and post-acute phases of SARS-CoV-2 infection and were independent of underlying pre-existing health conditions. The reduced risk of multisystem sequelae associated with a healthy lifestyle was consistently observed across participants, regardless of their vaccination status, disease severity (testing positive in community/outpatient settings or inpatient settings), and major SARSCoV-2 variants, including Omicron variants. The benefits were found to be larger than those observed in previous studies of pharmaceutical interventions in non-hospitalised patients. The authors conclude ‘These findings suggest the benefit of population adhering to a healthy lifestyle to reduce the potential long-term adverse health consequences of COVID-19.’

When it comes to diet, a number of studies have now shown that people who adhered most to a healthy plant-based diet had reduced severity and impacts from the infection, in part due to the favourable effects of a plant-based diet on the gut microbiome and hence inflammation and immune health.

Early Prostate Cancer Deaths Among Men With Higher vs Lower Genetic Risk

We often state that ‘genetics loads the gun but lifestyle pulls the trigger’. This new study provides a nice example of how this saying is true when considering cancer risk. The study included 19,607 men from two prospective cohorts the studies – the Malm Diet and Cancer Study (MDCS) in Sweden and the Health Professionals Follow-Up Study (HPFS) in the US, followed from 1991 to 2019. Data were analysed between April 2023 and April 2024. Men were categorised according to genetic risk (as defined by a polygenic risk score) and lifestyle behaviours and these were correlated with rates of prostate cancer death. Lifestyle behaviours included not smoking, high physical activity and a healthy weight. Positive dietary factors included high intakes of tomato-based products, high intake of fatty fish, and low intake of processed meat. Additional analysis expanded on dietary risk factors by including recommendations from the World Cancer Research Fund guidelines and also included high fibre and low dairy intake. You can find more detail in table 1 of the supplementary file.

The results showed that 67% of men were considered higher genetic risk for prostate cancer. During the median follow up of 24 years, 444 prostate cancer deaths were observed, of which 107 occurred by age 75 years and 337 after age 75 years. Both genetic and lifestyle factors were associated with higher rates of prostate cancer death. Those at higher genetic risk had a 3-fold increased risk rate of early (<75 years) and 2-fold increased risk of late prostate cancer death. It was calculated that up to 36% of all prostate cancer deaths occurring before the age of 75 years among men at higher genetic risk may have been prevented if healthy habits were adopted. The authors conclude, ‘These findings suggest that targeting men at increased genetic risk with prevention strategies may substantially reduce the number of early deaths from prostate cancer.’ The truth is that all communities need to be targeted with lifestyle advice and supported to adopt these healthy habits.

These results are very similar to studies conducted in people at various genetic risk of colorectal cancer and breast cancer

Cause-specific and all-cause mortalities in vegetarian compared with those in nonvegetarian participants from the Adventist Health Study-2 cohort

There is an open question as to whether plant-based diets, especially a 100% plant-based or vegan diet, impact life expectancy. This analysis from the Adventist Health Study-2 (large cohort of Seventh-day Adventists in the United States and Canada) investigated the relationship between different dietary patterns (including vegan, lacto-ovo vegetarian, pesco-vegetarian, semi-vegetarian, and non-vegetarian) and mortality risks. There is quite a bit of detail in the analysis, but I have summaried the key findings below. Of note, the most of the analysis presented compares vegetarians with non-vegetarians. The term vegetarian is inclusive of vegan, lacto-ovo vegetarian, pesco-vegetarian and semi-vegetarian (consuming meat between monthly to weekly).

1. Lower All-Cause Mortality in Vegetarians:
   • Vegetarians, including vegans, had a lower overall risk of all-cause mortality compared to non-vegetarians, particularly among younger individuals (e.g., at age 65). The hazard ratio (HR) for mortality in vegetarians at age 65 was 0.89 (95% CI: 0.83-0.95), indicating an 11% lower risk compared to non-vegetarians. However, this protective effect diminished with age, with no mortality advantage by age 85 years.
2. Specific Disease Mortality:
   • Renal Failure: Vegetarians, especially vegans, had a significantly lower risk of death from renal failure. The HR was 0.52 (95% CI: 0.38-0.70) at age 65 indicating a 48% lower risk. This advantage was maintained at age 85 years.
   • Infectious Diseases: Pescovegetarians had a lower risk of death from infectious diseases, with an HR of 0.41 (95% CI: 0.19-0.86)​ i.e. 59% lower risk at age 65 years. This advantage was not apparent at age 85 years.
   • Diabetes and Cardiac Diseases: Reduced risks in vegetarians were observed for deaths related to diabetes (30-50% reduction and cardiac conditions (10-25% reduction), including ischaemic heart disease at both 65 years and 85 years.
3. Increased Neurological Disease Mortality:
   • The study found that older vegetarians, particularly those aged 85 and above, had higher risk of death from certain neurological diseases, including stroke, dementia, and Parkinson’s disease.
   • Stroke: Higher risk of death from stroke among older vegetarians (17% increased risk)
   • Dementia: Increased risk of death from dementia (13% increased risk).
   • Parkinson’s Disease: A trend towards an elevated risk of death from Parkinson’s disease, although this was not statistically significant.
4. Ethnic Differences:
   • The trends observed in Black participants were generally similar to the overall cohort, but the results were less precise due to smaller sample sizes​.

Readers will be specifically interested in the health outcomes for vegans:

• General Impact: Vegans had a reduced risk of all-cause mortality at younger ages. At age 65, the hazard ratio (HR) for all-cause mortality among vegans was 0.88 (95% CI: 0.82-0.95), indicating a 12% lower risk compared to non-vegetarians. This benefit was greater in men than women. However, this benefit disappeared with age, and by age 85, there was no significant difference in mortality risk between vegans and non-vegetarians.
• Cause-Specific Mortality:
  • Renal Failure: Vegans had a particularly strong reduction in mortality risk from renal failure. At age 65, the HR was 0.37 (95% CI: 0.17-0.77), indicating a 63% lower risk. This advantage remained at age 85 years.
  • Other conditions: There were no additional advantages for a vegan diet.
  • Neurological Diseases:
    • Increased Risk at Older Ages: The study found that vegans, like other vegetarians, might have an increased risk of death from certain neurological diseases at older ages including stroke, dementia and Parkinson’s disease. However, these results were not statistically significant with the confidence intervals being very wide and crossing 1.
    • The impact of a vegan diet on the risk of Parkinson’s disease, was analysed in the supplemental data of the study. The results indicate that vegans had a lower prevalence of Parkinson’s disease at baseline compared to non-vegetarians. The prevalence was 0.37% in vegans compared to 1.13% in non-vegetarians​. However, when looking at the risk of mortality from neurological diseases (which includes Parkinson’s disease and other neurological conditions), the study’s results were not as conclusive. For vegans at age 65 years, the hazard ratio (HR) for neurological disease mortality was slightly lower than that of non-vegetarians, but the confidence intervals crossed 1.0, indicating that the reduction in risk was not statistically significant across all comparisons​. So while there seems to be a lower baseline prevalence of Parkinson’s disease among vegans, the overall impact of a vegan diet on mortality from neurological diseases remains less clear and may require further investigation to establish more definitive conclusions.

Summary of findings:

The study suggests that vegetarian diets (i.e. low meat and meat-free diets) are associated with lower risks of all-cause mortality and several specific causes of death, particularly in younger individuals i.e. reduction in risk of premature mortality. There is also a significant advantage at both younger and older ages for a reduction in risk of death from diabetes, kidney failure and cardiac conditions. However, this advantage in older age seems to be offset by a potential increased risk of mortality from neurological diseases especially Parkinson’s disease in older lacto-ovo-vegetarians, stroke deaths in older vegans and lacto-ovo-vegetarians, and dementia (all older vegetarians combined). Thus, at 85 years the overall mortality advantage has disappeared. The authors sensibly suggest that the impact on brain health may be due to the fact the vegetarian diet patterns tend to have lower or no intakes of long-chain omega-3 fatty acids (DHA/EPA), which we mostly obtain from eating fish. Hence, this study may indicate that people consuming a diet without fish should be supplementing with algae-derived DHA and EPA. In addition, low and no meat diets ten to have lower intakes of vitamin B12 and hence supplementation needs to be prioritised.

*Hot of the press, a study using data from the UK Biobank cohort has reported a significant advantage for physical activity in reducing the risk of Alzheimer’s dementia and Parkinson’s disease. This positive impact was accentuated by adherence to a higher quality/healthy plant-based diet.*

Ultra-processed foods and cardiovascular disease: analysis of three large US prospective cohorts and a systematic review and meta-analysis of prospective cohort studies

The dialogue around the health impacts of ultra-processed foods (UPFs) continues, with many suggesting we should shun all UPFs given their negative impact on health. However, not all UPFs are created equal and the commonly used NOVA classification only considers the degree of food processing without considering a foods impact on health. A steak, classified as being an unprocessed food, is then wrongly considered as healthy whereas a plant-based meat alternative made of soya or seitan would be considered ultra-processed and regarded as less healthy, despite the evidence suggesting otherwise.

So it’s good to have more studies that assess the impact of subgroups of UPFs rather than putting them all together as if they were a homogenous group. This paper including more than 200,000 participants from the Nurses’ Health Studies and the Health Professionals Follow Up Study. It found that higher intake of UPFs was associated with an increased risk of cardiovascular disease (CVD) and coronary heart disease (CHD), but not stroke. A further analysis of pooled data from 19 cohort studies was also conducted. This found that total UPF consumption was associated with a significant increase in CVD, CHD and stroke. However, these associations were largely driven by consumption of processed meat, sugar-sweetened beverages and artificially-sweetened beverages. Ultra-processed savoury snacks, cold cereals, and yoghurt/dairy-based desserts were inversely associated with CVD and CHD risk. Ultra-processed bread and cold cereals were associated with lower stroke risk. When removing processed meat and sugar-sweetened beverages from total UPFs, the negative impact on cardiovascular health disappeared.

This is not the first study to show such results. A meta-analysis assessing the impact of UPFs on all-cause and cause-specific mortality found an association between higher consumption of UPFs and increased risk of all-cause mortality but this association was mostly driven by consumption of meat/poultry/seafood based ready-to-eat products. Analysis from the EPIC (European Prospective Investigation into Cancer and Nutrition) study showed that higher consumption of UPFs was associated with co-occurrence of multiple comorbidities relating to cancer and cardiometabolic health, but again this association was with the consumption of animal-based products and artificially and sugar-sweetened beverages. Other subgroups such as ultra-processed breads and cereals or plant-based meat and dairy alternatives did not show an adverse impact on health. Similarly and hot of the press, another analysis from the EPIC cohort study has shown that consumption of UPFs are associated with an increased risk of type 2 diabetes. However, UFP subgroups had differing effects. Savoury snacks, animal-based products, ready-to-eat/heat mixed dishes and artificially- and sugar-sweetened beverages were associated with higher incidence of type 2 diabetes, whereas breads, biscuits and breakfast cereals, sweets and desserts, and plant-based alternatives were associated with lower incidence.

So you get the point. Not all UPFs are created equal and they should not be considered a homogenous group since different subgroups or categories of UPFs having differing effects on health outcomes.

Association of plant‑based diets with total and cause‑specific mortality across socioeconomic deprivation level: a large prospective cohort

Addressing social determinants of health is key to improving population health. In the UK, Sir Michael Marmot has spent his career researching and highlighting the negative impact of socioeconomic deprivation on health outcomes. Successive reports have shown that life expectancy is falling in the poorest areas in the UK and that health inequalities are widening. On average, people living in the most deprived areas of the UK spend up to 20 years in ill health. In response to his life’s work he has set up the Institute of Health Equity to provide solutions. He and his team have developed the concept of Marmot Places and work with these areas to implement interventions to improve health equity.

It is interesting to read this paper on the impact of plant-based diets on health outcomes based on the level of socioeconomic deprivation. My favourite plant-based diet index has been used to assess diet quality in 189,003 participants of the UK Biobank study.During a median follow-up of 9.6 years, 9335 deaths were documented. Those most adherent to an overall plant-based diet had a 13% and 23% reduction in all cause and cardiovascular mortality, respectively. Those most adherent to a healthy plant-based diet had in addition significant reductions in respiratory, neurological and cancer-related mortality. Consumption of an unhealthy plant-based diet was associated with increased mortality. When considering socioeconomic deprivation as determined by the Townsend deprivation index, the strength of association was greater in those participants from the most deprived areas. The authors conclude ‘Sticking to a healthy plant-based diet may help decrease mortality risks across socioeconomic deprivation levels, especially for those who are the most socioeconomically deprived.’ However, it should be noted that the absolute impact on mortality and extra life expectancy was small – in the order of days to months rather than years. This may be because even in those participants most adherent to a plant-based diet, the fibre intake was only 19g per day. This is well below recommended and shows that overall diet quality in this cohort was suboptimal.

We have a good level of evidence to suggest that community level interventions to increase consumption of fruit and vegetables can improve diet quality and health outcomes. In the US, a 6 month long intervention of fruit and vegetables prescription in children and adults with cardiometabolic risk factors led to significant improvement in diet quality, food security and health indicators. Similar results have been reported from a trial of fruit and veg prescription in London, UK.

A systematic review and meta-analysis of randomized trials of substituting soymilk for cow’s milk and intermediate cardiometabolic outcomes: understanding the impact of dairy alternatives in the transition to plant-based diets on cardiometabolic health

An important question in nutrition science is always ‘instead of what?’ When considering a change in diet, one needs to consider what is being removed and what has replaced that food in the diet. Cow’s milk has always been considered a healthy addition to the diet of children and adults, mainly because it is better for health than other commonly consumed drinks such as fruit juice and sugar-sweetened beverages. But I always tell my patients that they can make an even better choices i.e. swapping cows milk for a soya drink. I felt I already had sufficient evidence to recommend this swap given the extensive scientific evidence supporting the consumption of soya and its beneficial impact on health. But more data is always useful!

This is a new systematic review and meta analysis of 17 randomised controlled trials that compared cow’s milk to soya milk consumption and the impact on cardiometabolic health. The analysis showed that soya milk improves cardiovascular risk factors, including LDL-cholesterosl, blood pressure and C-reactive protein, a marker of inflammation. Interestingly, there was no difference in results when considering soya milk with and without added sugar. The authors rightly conclude ‘our findings support the use of fortified soya milk with up to 7 g added sugars per 250 mL as a suitable replacement for cow’s milk and suggest that its classification as ultra-processed and/or not healthy based on small amounts of added sugars may be misleading and need to be reconsidered to facilitate the recommended transition to plant-based diets.’

Once again it is clear that classifying foods based on the level of processing does not necessarily correlate with health outcomes. In addition, it is clear that switching to soya milk would be a more sustainable choice with significant benefits for planetary health. This can no longer be overlooked given the fact that planetary health is also in need of ‘intensive care’.

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