The PLoS ONE review’s main results found consuming butter was weakly associated with all-cause mortality, was not significantly associated with any CVD, coronary heart disease or stroke and was inversely associated with the incidence of diabetes.
In total, the combined group of studies included 28,271 deaths, 9,783 cases of CVD, and 23,954 cases of new-onset type 2 diabetes. The researchers combined the nine studies into a meta-analysis of relative risk.
"Even though people who eat more butter generally have worse diets and lifestyles, it seemed to be pretty neutral overall," said Dr Laura Pimpin, former postdoctoral fellow at the Friedman School of Nutrition Science and Policy at Tufts in Boston.
"This suggests that butter may be a more healthful choice than sugar or starch, and a worse choice than many margarines and cooking oils - those rich in healthy fats such as soybean, canola, flaxseed, and extra virgin olive oils," she added.
The findings are sure to ignite opposition from health campaigners, who believe butter’s high saturated fat content has the effect on heightening risk of chronic conditions such as heart disease and type 2 diabetes.
The World Health Organization (WHO) states that CVD causes more than half of all deaths across Europe.
CVD causes 46 times the number of deaths and 11 times the disease burden caused by AIDS, tuberculosis and malaria combined in Europe. 80% of premature heart disease and stroke is preventable.
A review that looked at nine research papers involving 15 country-specific cohorts was analysed. All in all, 636,151 individuals took part in the analysis. Butter consumption was kept consistent in the studies to 14 grams/day.
Butter consumption across the studies ranged from around one-third of a serving per day to 3.2 servings per day.
The effects of butter consumption over a longer period and its influence on all-cause mortality and CVD, are not well-established.
In response to the review’s findings, Tom Sanders, Professor emeritus of Nutrition and Dietetics at King’s College London highlighted a limitation of the review commenting that in some of the prospective studies in serum cholesterol at baseline and intake of monounsaturated and polyunsaturated fatty acids were adjusted for difference.
“The finding is not surprising as 14 g butter per day would only be expected to change blood cholesterol level by 1% and this alone would have an unnoticeable effect on risk of CVD,” he said.
“The studies were also unable to make any allowance for butter in processed foods such as cake and biscuits. Generally, I agree with the review that it is the overall dietary pattern that matters rather than the intake of specific food items.”
Tracy Parker, heart health dietitian at the British Heart Foundation, added: “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.”
According to the Eatwell Guide, the UK's official dietary advice, the average man should have no more than 30 g saturated fat a day and average woman should have no more than 20 g saturated fat a day.
Source: PLoS ONE
Published online ahead of print, doi:10.1371/journal.pone.0158118
“Is Butter Back? A Systematic Review and Meta-Analysis of Butter Consumption and Risk of Cardiovascular Disease, Diabetes, and Total Mortality.”
Authors: Pimpin L, Wu JHY, Haskelberg H, Del Gobbo L, Mozaffarian D