Butter doesn?t increase risk of heart disease after all

[Gert van der Hoek]

JUNE 29, 2016

Butter, that beloved fatty staple, has been slowly welcomed back into Americans? diets ? and a new study finds it isn?t as bad for our arteries as once believed.

Why it matters:

Americans are eating more butter than they have in a generation. And the latest diet evidence indicates that saturated fats aren?t as bad for heart health as previously believed. Guidelines shunning saturated fats (found in animal products like red meat and dairy) arose largely out of the 1970 Seven Countries Study, which found that populations consuming high levels of saturated fats had high levels of heart disease. But studies since then have painted a more nuanced picture, with many questioning the demonization of saturated fats.

Nowadays scientists are increasingly looking not at broad categories like ?saturated fat? but rather at the healthfulness of specific foods, such as butter. But there hasn?t yet been a review of the science focusing specifically on butter.

The nitty gritty:

Researchers combined the data from nine studies looking at the relationship of butter consumption with various health outcomes. They found that eating butter didn?t significantly change people?s incidence of cardiovascular disease, coronary heart disease, or stroke. The study did find a small link between butter and overall mortality ? each daily tablespoon of butter was linked to a 1 percent increase in mortality risk. On the other hand, the same amount of butter was associated with a 4 percent lower risk of diabetes.

?This is neither a health food that should be sought out, and on the other hand it?s not a food that should be avoided at all costs,? said Dr. Dariush Mozaffarian, an epidemiologist at Tufts University and one of the study?s senior authors. The findings were published Wednesday in PLOS ONE.

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[Gert van der Hoek]

Is Butter Back? A Systematic Review and Meta-Analysis of Butter Consumption and Risk of Cardiovascular Disease, Diabetes, and Total Mortality

June 29, 2016

Abstract

Background

Dietary guidelines recommend avoiding foods high in saturated fat. Yet, emerging evidence suggests cardiometabolic benefits of dairy products and dairy fat. Evidence on the role of butter, with high saturated dairy fat content, for total mortality, cardiovascular disease, and type 2 diabetes remains unclear. We aimed to systematically review and meta-analyze the association of butter consumption with all-cause mortality, cardiovascular disease, and diabetes in general populations.

Methods and Findings

We searched 9 databases from inception to May 2015 without restriction on setting, or language, using keywords related to butter consumption and cardiometabolic outcomes. Prospective cohorts or randomized clinical trials providing estimates of effects of butter intake on mortality, cardiovascular disease including coronary heart disease and stroke, or diabetes in adult populations were included.

One investigator screened titles and abstracts; and two reviewed full-text articles independently in duplicate, and extracted study and participant characteristics, exposure and outcome definitions and assessment methods, analysis methods, and adjusted effects and associated uncertainty, all independently in duplicate. Study quality was evaluated by a modified Newcastle-Ottawa score. Random and fixed effects meta-analysis pooled findings, with heterogeneity assessed using the I2 statistic and publication bias by Egger’s test and visual inspection of funnel plots.

We identified 9 publications including 15 country-specific cohorts, together reporting on 636,151 unique participants with 6.5 million person-years of follow-up and including 28,271 total deaths, 9,783 cases of incident cardiovascular disease, and 23,954 cases of incident diabetes. No RCTs were identified.

Butter consumption was weakly associated with all-cause mortality (N = 9 country-specific cohorts; per 14g(1 tablespoon)/day: RR = 1.01, 95%CI = 1.00, 1.03, P = 0.045); was not significantly associated with any cardiovascular disease (N = 4; RR = 1.00, 95%CI = 0.98, 1.02; P = 0.704), coronary heart disease (N = 3; RR = 0.99, 95%CI = 0.96, 1.03; P = 0.537), or stroke (N = 3; RR = 1.01, 95%CI = 0.98, 1.03; P = 0.737), and was inversely associated with incidence of diabetes (N = 11; RR = 0.96, 95%CI = 0.93, 0.99; P = 0.021). We did not identify evidence for heterogeneity nor publication bias.

Conclusions

This systematic review and meta-analysis suggests relatively small or neutral overall associations of butter with mortality, CVD, and diabetes. These findings do not support a need for major emphasis in dietary guidelines on either increasing or decreasing butter consumption, in comparison to other better established dietary priorities; while also highlighting the need for additional investigation of health and metabolic effects of butter and dairy fat.

LINK TO FULL ARTICLE