June 29, 2016

expert reaction to paper looking at butter consumption and cardiovascular disease, diabetes and mortality

Publishing in PLOS ONE, a systematic review and meta-analysis by scientists at Tufts University in Boston looked at the associations between butter consumption and mortality, cardiovascular disease and diabetes.

Prof Tom Sanders, Professor emeritus of Nutrition and Dietetics, King’s College London, said:

“A significant limitation of this review is that some of the prospective studies adjusted for difference in serum cholesterol at baseline as well as other aspects of diet, including a healthy eating index and the intake of monounsaturated and polyunsaturated fatty acids.

“However, the finding is not surprising as 14g butter per day would only be expected to change blood cholesterol level by 1% and this alone would have an imperceptible effect on risk of CVD.

“The studies were also unable to make any allowance for butter in processed foods such as cake and biscuits.

“There is some speculation in the discussion that butter may provide extra vitamin D. However, this is mistaken as butter is a poor source of vitamin D and it is margarine that is fortified with vitamin D.

“Generally, I agree with the review that it is the overall dietary pattern that matters rather than the intake of specific food items.”

Prof Pete Wilde, Research Leader, Food and Health Programme, Institute of Food Research, said:

“This study appears to add to the evidence that whilst many dairy products can be beneficial to health when consumed in moderation, higher fat products can mitigate this beneficial effect, so this certainly isn’t carte blanche to consume large amounts of butter. This study was normalised to a 14g per day intake (which is roughly an average intake) but other studies show a dose response indicating an increased risk with increased intake of high fat dairy products.

“As mentioned in the article, the consumption of many dairy products has been linked with a range of positive health benefits. The biggest effects are seen with lower fat dairy products, but some positive effects are also seen with cheese consumption. These products have a much lower fat content than butter, and it is thought that the positive health effects are linked to the water soluble compounds such as the vitamin, mineral and protein content. Butter on the other hand consists of about 80% milk fat, with only 20% water, so a lot of the protein, minerals etc. are lost. The fat is also high in saturated fat but does contain a fair amount of the fat soluble vitamins, especially vitamin A.

“Other studies have also shown that high fat dairy products give a small increase in risk of CVD, and are neutral in terms of total mortality, but lower fat content dairy products are linked to reduced risk overall. Other analyses also show some U shaped curves, with moderate consumption reducing risk, but higher levels of consumption could lead to an increased risk.

“Also, it is not clear how associated lifestyle affects this relationship. It could be that consumers of butter also consume a range of other dairy products.”

Tracy Parker, Heart Health Dietitian at the British Heart Foundation, said:

“Understanding the true relationship between diet and our health is difficult, but we know that replacing saturated fat with unsaturated fats seems to have a positive impact on our heart health and this is recognised by the authors of this study.

“Whilst the findings of this review indicate a small or neutral association between butter consumption and increased cardiovascular risk, it does not give us the green light to start eating more butter. More investigations are needed into the effects of saturated fat.

“What we do know is fat is just one element of our diet. There are many factors which cause cardiovascular disease and no single food or nutrient is solely responsible for this. To protect your heart health we would recommend a balanced Mediterranean style diet rich in fruit, vegetables and pulses.”

‘Is butter back? A systematic review and meta-analysis of butter consumption and risk of cardiovascular disease, diabetes, and total mortality’ by Laura Pimpin et al. published in PLOS ONE on Wednesday 29 June 2016.

Declared interests

Prof. Tom Sanders: “Prof Tom Sanders is a Scientific Governor of the charity British Nutrition Foundation, member of the scientific advisory committee of the Natural Hydration Council (which promotes the drinking of water), and honorary Nutritional Director of the charity HEART UK. Prof. Tom Sanders is now emeritus but when he was doing research at King’s College London, the following applied: Tom does not hold any grants or have any consultancies with companies involved in the production or marketing of sugar-sweetened drinks. In reference to previous funding to Tom’s institution: £4.5 million was donated to King’s College London by Tate & Lyle in 2006; this funding finished in 2011. This money was given to the College and was in recognition of the discovery of the artificial sweetener sucralose by Prof. Hough at the Queen Elizabeth College (QEC), which merged with King’s College London. The Tate & Lyle grant paid for the Clinical Research Centre at St Thomas’ that is run by the Guy’s & St Thomas’ Trust, it was not used to fund research on sugar. Tate & Lyle sold their sugar interests to American Sugar so the brand Tate & Lyle still exists but it is no longer linked to the company Tate & Lyle PLC, which gave the money to King’s College London in 2006. Tom also used to work for Ajinomoto on aspartame about 8 years ago.  Tom was a member of the FAO/WHO Joint Expert Committee that recommended that trans fatty acids be removed from the human food chain. Tom has previously acted as a member of the Global Dairy Platform Scientific Advisory Panel and Tom is a member of the Programme Advisory Committee of the Malaysian Palm Oil Board. In the past Tom has acted as a consultant to Archer Daniel Midland Company and received honoraria for meetings sponsored by Unilever PLC. Tom’s research on fats was funded by Public Health England/Food Standards Agency.”

Prof. Pete Wilde: “I don’t think I have any relevant interests to declare.  I am employed by the Institute of Food Research, member of the Royal Society of Chemistry, and treasurer of its Food Group committee.  My funding comes mainly from the BBSRC, and other governmental sources. I do have a small amount of industry funding, but nothing to do with dairy products, and concerns sensory aspects of food structures and not with nutrition and health. I have no position outside of the IFR with any decision making or policy changing powers. I am an honorary Professor at the University of East Anglia (School of Pharmacy).”

Tracy Parker: “No interests to declare.”