by Mick Walker and Shireen Kassam, on behalf of Plant-Based Health Professionals UK

Dear Editor,

We are writing with regard to the article by Joanna Blythman in the Observer on 26th September, titled ‘ Food myths busted : dairy, salt and steak may be good for you after all’.

The article is factually inaccurate and misinformed, to the extent that we would classify this as misleading and irresponsible journalism.

The discussion is centred around a paper recently published the journal Plos Medicine assessing the impact of dairy fat consumption on health outcomes. At no point does the paper mention the consumption of steak or salt — so it would appear that reference to these has been added to increase the appeal of the article.

Before we take issue with the conclusions of the study, we would like to question some of the other claims made by the author.

She refers to meat, dairy and eggs being natural foods for human beings. It is entirely legitimate to question this statement. Incarcerating billions of animals in appalling conditions then slaughtering them is hardly natural. Milk is produced by mother cows, specifically to feed their calves — killing many of these calves and stealing the milk for human consumption can hardly be regarded as natural. Neither can the stealing of eggs from birds which are kept in huge numbers in dreadful, cramped conditions.

When she refers to ‘mother nature’ providing us with these foods, the intensive animal agriculture industry can hardly be equated with ‘mother nature’. Nor can it be said to have come about during the normal course of evolution.

The article says ‘Our ancestral diet has included meat for millions of years’. The general consensus is that Homo sapiens appeared around 315,000 years ago and that little if any meat was consumed till we invented agriculture around 10–12,000 years ago. There is absolutely no evidence that meat was a major part of the human diet before then. Instead, our Paleolithic ancestors ate large amounts of wild fruits and vegetables, more than even modern-day vegans, with typical fibre intakes of 100g per day.

The claim that fruit and vegetables compare poorly with nutrient dense dairy, meat, fish and eggs is ridiculous as is the claim that eggs are one of the most nutrient rich foods you can eat. The concern expressed about the high (natural) sugar levels in fruit is, frankly, a purposeful misinterpretation of the scientific literature. High consumption of fruits and vegetables have been shown in numerous publications to be associated with a reduced risk of our common chronic illnesses, including type 2 diabetescardiovascular disease, cancer and a longer life.

We would agree that many people are consuming too much in the way of refined grains and free sugars. However, whole food sources of carbohydrates, such as whole grains and beans, are key components of a healthy diet, with lower carbohydrate diets specifically associated with adverse health outcomes such as cardiovascular disease, cancer and early death.

At one point the author suggested that the NHS Eatwell Guide is not evidence-based, which could not be further from the truth. Studies have shown that if we actually followed the advice within the Eatwell guide the health of the UK population would certainly be improved. To suggest that consuming red meat and salt are good for health is being dishonest and misleading. Red meat consumption has been conclusively linked to an increased risk of chronic disease. Excessive salt consumption is the leading dietary risk factor for premature death globally, including the UK, and there are clear benefits documented within the scientific literature to limiting salt consumption in the diet. The main one is a reduction in the risk of high blood pressure, a condition that affects at least one in four adults in the UK and is the leading cause of heart attacks, strokes and kidney failure.

The recent paper that the article refers to investigated the association between dairy consumption and the risk of cardiovascular disease. The researchers measured levels of certain biomarkers in the blood of 4150 people, of which 51% were women and with an overall median age of 60.5 years. In addition they included a meta-analysis of a further 18 studies.

The biomarkers used were three ‘Odd-Chain’ fatty acids — pentadecanoic acid (referred to as 15 in the study), heptadecanoic acid (referred to as 17 in the study) and trans-palmitoleic acid. The rationale was that these biomarkers are produced in the guts of ruminants (they are) and that their presence in the blood is a good indication of the level of dairy consumption. In the paper, they admitted that the biomarkers could not distinguish what types of dairy products had been consumed. Also, that the biomarkers were only measured once, and the assumption was made that people tend to eat a similar diet most of the time. The paper also stated that dairy products are a major dietary source of propionate, a short chain fatty acid, which is a primary substrate for the synthesis of odd-chain fatty acids.

What the paper didn’t mention was that the odd-chain fatty acids produced in the guts of ruminants are a result of microbial fermentation. Now it is very clear that one of the huge benefits of a high fibre diet is that bacteria in our large intestine also produce several short chain fatty acids, including propionate (as well as butyrate and acetate). This being the case, it may well be that fibre consumption is probably much more correlated with odd-chain fatty acids in the blood than dairy consumption. Indeed, several studies have shown this to be the case and the level of biomarker 17 is as high in the blood of vegans as was taken to be an indicator of dairy consumption in the study. So odd-chain fatty acids are probably a more reliable indicator of fibre consumption than dairy. None of these issues were discussed by Joanna Blythman.

There are many studies to show that the presence of odd-chain fatty acids in the blood is also significantly associated with the consumption of fruit and vegetables and that propionate helps to reduce cholesterol absorption. In terms of reducing the risk of cardiovascular disease, there are many studies that demonstrate the benefit of a high fibre diet.

The third biomarker (trans-palmitoleic acid) is not associated with fibre intake and was NOT shown to be of significance in the study.

Dairy is high in saturated fat, and in fact, many studies have confirmed that the lowering of saturated fat in the diet significantly reduces the risk of cardiovascular disease. The only studies to show that heart disease can be arrested and possibly reversed are one that have used a dietary approach which is very low in fat, such Dr Ornish’s Program for Reversing Heart Disease, reimbursed by Medicare and Medicaid Services in the USA. Population based dietary interventions such as the North Karelia project in Finland that limited the consumption of meat and dairy fat, demonstrated a reduction in cardiovascular disease mortality by 84%.

Setting aside the impact of dietary choices on human health, we must not forget that we are in the midst of climate and ecological collapse, having already entered the sixth mass extinction event. Animal agriculture is a leading cause of these global crises, with the production of red meat and dairy being the most harmful. We must reduce if not eliminate our consumption of red meat and dairy and without a change in the food system we will not meet our climate targets. Articles suggesting otherwise are highly irresponsible.

It is clear that the article written by Joanna Blythman is inaccurate and misleading. We call for an immediate retraction of this article.

Yours Sincerely

Mick Walker and Shireen Kassam, on behalf of Plant-Based Health Professionals UK