Does butter deserve its bad rap? A meta-analysis examines butter consumption and type 2 diabetes, as well as mortality and cardiovascular disease.
Despite its bad rap, butter may not be such a villain after all, according to results from a meta-analysis that suggests “relatively small” or “neutral” associations between butter consumption and long-term health.
The results were published online in PLoS ONE.1
While past meta-analyses have looked at links between butter and total mortality and CVD-and found little evidence for an association-the study is the first meta-analysis to look at butter consumption and T2DM.
“In this systematic review and meta-analysis of prospective studies, we found a small positive association between butter consumption and all-cause mortality, no significant association with incident CVD or CVD subtypes, and a modest inverse association with type 2 diabetes,” wrote first author Laura Pimpin, PhD, of Tufts University (Boston, MA), and colleagues.
“In sum, our findings do not support a need for [a] major emphasis in dietary guidelines on butter consumption, in comparison to other better established dietary priorities,” they added.
Guidelines have long advised against eating too much saturated fat. A current criticism, though, is that guidelines have underplayed the diversity of food sources and their individual fatty acid profiles. The issue concerns a wider problem: concentrating on isolated nutrients rather than the overall dietary pattern.
Evidence linking butter, which ranks high in saturated fat, to total mortality, cardiovascular disease, and T2DM is unclear, with some studies have suggested a protective effect. That, coupled with a 40-year high in butter consumption, according to the USDA, makes butter a weighty issue.2
In the study, researchers examined nine databases from inception to May 2015, without setting or language restrictions. To be included, studies had to evaluate the association between butter consumption and mortality, CVD, or diabetes in adults. The analysis included nine studies, which covered 636,151 participants, 28,271 deaths, 9783 incident cases of CVD, and 23,954 incident cases of diabetes. No randomized controlled trials were identified.
Key results for the association between butter consumption and:
• All-cause mortality: Weak associations
♦ Each daily serving of butter (14 g/d, or one tablespoon) was linked to 1% higher risk of death (RR=1.0134 (95% CI=1.0003, 1.0266; P=0.045)
• No significant association with:
♦ Cardiovascular disease: RR=1.00, 95% CI=0.98, 1.02; P=0.704
♦ Coronary heart disease: RR=0.99, 95% CI=0.96, 1.03; P=0.537
♦ Stroke: RR=1.01, 95% CI=0.98, 1.03; P=0.737
• Diabetes: Slightly decreased risk (RR=0.96, 95% CI=0.93, 0.99; P=0.021)
♦ Moderate heterogeneity between studies (I2=42.1%, P=0.131)
• No significant evidence for heterogeneity or publication bias
The authors contrasted these results to the “clear harmful effects” of refined grains, starches, and sugars on cardiometabolic risk, and emphasized the benefits of fruits, nuts, legumes, vegetable oils, and fish. They also acknowledged the adverse effects of dairy fats on cardiometabolic risk factors like LDL. Other mechanisms may be at play that offset these risk factors, they suggested, though these remain to be determined.
“In sum, these results suggest that health effects of butter should be considered against the alternative choice. For instance, butter may be a more healthful choice than the white bread or potato on which it is commonly spread,” they stressed, “In contrast, margarines, spreads, and cooking oils rich in healthful oils, such as soybean, canola, flaxseed, and extra-virgin olive oil, appear to be healthier choices than either butter or refined grains, starches, and sugars.”
• Dietary guidelines have long advised against eating too much saturated fat, though such guidelines have underplayed the diversity of food sources and their individual fatty acid profiles.
• A meta-analysis of nine studies found a small positive link between butter consumption and all-cause mortality, no significant links with CVD, and a modestly decreased risk of T2DM.
• The authors suggest the “relatively small” or “neutral” effects of butter on long-term health should be considered against the backdrop of the “clear harmful effects” of refined grains, starches, and sugars.
Dr. Mozaffarian reports ad hoc honoraria, consulting, royalties, and/or advisory board membership for one or more of the following: Boston Heart Diagnostics, Haas Avocado Board, Astra Zeneca, GOED, Life Sciences Research Organization, UpToDate, and/or Elysium Health. Dr. Mozaffarian is listed as one of three co-inventors on a patent for “Use of transpalmitoleic acid in identifying and treating metabolic disease.”
1. Pimpin L, et al. Is butter back? A systematic review and meta-analysis of butter consumption and risk of cardiovascular disease, diabetes, and total mortality. PLoS One. 2016 Jun 29;11(6):e0158118.
2. Bentley J, ed. USDA Economic Research Service. Food Availability (Per Capita) Data System, December 2014.