The headlines were buzzing last week when a new meta-analysis was published that added to the emerging science around dairy fat, but this time the food implicated was a bit of a surprise: butter.
Emerging science indicates consumption of milk, cheese and yogurt, including whole, reduced-fat, low-fat and fat-free, has either neutral or beneficial links to cardiovascular disease risk. The conversation has generally been focused on milk, cheese and yogurt because there is not much published research on how butter is linked to health outcomes, even though research indicates that saturated fat in general is largely neutral in terms of link to disease risk.
The current analysis was based on nine publications from 15 different population cohort studies, with the number of study participants totaling 636,151 individuals. Butter consumption across studies were standardized at a level 14 g/d, which corresponds to one tablespoon. The researchers found butter consumption was:
- “Weakly associated” with all-cause mortality
- Not associated with cardiovascular disease, coronary heart disease or stroke
- Associated with reduced risk of Type 2 diabetes
The authors report that these findings add to a growing body of evidence on long-term health effects linked to specific foods and types of fats, and further make the case for a food-based, rather than nutrient-based, approach to dietary guidance. Indeed, understanding the link of foods rather than the nutrients that make up foods is an important piece of the nutrition puzzle, and could provide some clarity with regard to the new and emerging research that consumption of dairy foods, including whole, reduced-fat, low-fat and fat-free milk, cheese and yogurt is not associated with cardiovascular disease risk. In some cases, blood markers of dairy fat consumption have actually been linked to a reduced risk of Type 2 diabetes, and in the present study, one finding was that butter consumption was linked to reduced incidence of Type 2 diabetes.
As someone who follows the daily grind of nutrition research, another point the authors made that struck me was the relative lack of research published on butter – only nine studies met their rigorous inclusion criteria for analysis – “Considering the number of large prospective studies globally having data on dietary habits (including butter consumption) and these outcomes, it is evident that many additional cohort studies have collected such data but not analyzed or reported their findings. Such ‘missing,’ unpublished studies may be more likely to have null effects.”
In other words, there may be a potential publication bias (i.e., publication of only large associations rather than null or no associations). Based on relationships between saturated and LDL cholesterol, there may have been an assumption of a link with disease risk and few researchers have asked the more food-centric question about butter’s associations with health outcomes.
In science’s quest to learn everything about each individual nutrient, have we neglected to ask enough questions about foods? Prior to this paper, we already learned that cheese consumption (compared to butter consumption) may not result in the expected increase in LDL cholesterol. So clearly, given the emerging science on milk, cheese, yogurt and now butter, we need to ask more of these food-centric research questions.
It should be noted that all of these studies are observational in nature and do not establish cause and effect. Nonetheless, this study adds to the growing body of literature that saturated fat is not associated with cardiovascular disease risk, this study also makes interesting observations that we should not assume foods are just a reflection of a single nutrient or ingredient. We need more studies examining the associations and effects of foods on health outcomes, because foods like butter may be more than just the sum of their parts.