A meta-analysis study, involving over 600,000 participants, shows no clear signs of butter being a health risk.
The study showed that there was a weak association between butter consumption and total mortality, no association was found between butter and heart disease and, furthermore, butter was linked with a reduced risk of diabetes (which largely means type 2 diabetes).
A meta-analysis combines the results and data from a range of studies to draw conclusions that apply to a much larger group of participants. The research team, led by researchers from Tufts University in Bosto, reviewed data from nine studies involving 636,151 participants and 6.5 million person years of follow-up.
Within the participants included in the analysis, there were:
28,271 total deaths
9,783 cases of incident cardiovascular disease (including heart disease and stroke)
23,954 cases of incident diabetes
Butter consumption across the nine studies varied between a third of a serving to 3.2 servings, whereby a serving represents 14g of butter (equivalent to one tablespoon of butter).
The results showed the following the following increases and decreases associated with one 14g serving of butter consumption:
1% increase in all-cause mortality
No increase or decrease for cardiovascular disease in general
1% decrease in coronary heart disease
1% increase in stroke
4% decrease in incidence of diabetes
Dr. Dariush Mozaffaria, Dean of the Tufts Friedman School of Nutrition Science and Policy, states: “Overall, our results suggest that butter should neither be demonized nor considered ‘back’ as a route to good health.”
Dr. Laura Pimpi, former postdoctoral fellow at the Friedman School of Nutrition Science and Policy at Tufts, noted that: “people who eat more butter generally have worse diets and lifestyles.” However, whilst this is true for most of the studies used in the meta-analysis, this is a trend that is beginning to change.
In recent years, butter has begun to make a gradual comeback as more people are recognising it as not being the harmful food that late twentieth century health guidelines painted it as being. In fact Dr. Pimpin states that in terms of health or harm, butter is “pretty neutral overall”.
Dr. Mozaffarian added that it will be of interest to investigate more into why butter showed a 4 per cent reduced risk of incidence of diabetes, stating: “More research is needed to better understand the observed potential lower risk of diabetes, which has also been suggested in some other studies of dairy fat. This could be real, or due to other factors linked to eating butter – our study does not prove cause-and-effect.”
Readers may be interested to note that the study that showed the lowest rates of diabetes being linked with butter consumption was a very recent 2015 study within Sweden. Within the Swedish study, by Ericson et al., the incidence of diabetes associated was 7 per cent lower for each serving of butter.
The key point about this study is that since 2008, a low carb, high fat diet with low reliance on processed foods has gained significant traction in being recognised as a healthy diet. This suggests that butter can be safely adopted as part of a healthy, low carb, high fat real-food diet.
The meta-analysis is published online of the PLOS ONE journal.