Healthy low-carb, low-fat diets may lower CHD risk

The healthy versions of low-carbohydrate (LCD) and low-fat diets (LFD) appear to reduce the risk of coronary heart disease (CHD), suggests a study.

A total of 42,720 men in the Health Professionals Follow-Up Study (HPFS) (1986-2016), 64,164 women in the Nurses’ Health Study (NHS) (1986-2018), and 91,589 women in NHSII (1991-2019) were followed for CHD incidence.

The authors derived five LCD and five LFD indices based on food frequency questionnaire (FFQ) assessments. Each index highlights different sources and qualities of macronutrients (animal products vs plant-based foods, whole grains vs refined carbohydrates, etc). They also developed multimetabolite scores of LCD and LFD indices via elastic net regression in 1,146 healthy participants in the lifestyle validation studies (LVS), substudies embedded in the NHS/NHSII/HPHS.

Some 20,033 CHD cases were documented over 5,248,916 person-years of follow-up. When comparing the highest with the lowest LCD scores, the pooled adjusted hazard ratios (aHRs) for CHD were 1.05 (95 percent confidence interval [CI], 1.01‒1.10) for overall LCD, 1.07 (95 percent CI, 1.02‒1.12) for animal LCD, 0.94 (95 percent CI, 0.90‒0.99) for vegetable LCD, 1.14 (95 percent CI, 1.09‒1.20) for unhealthy LCD, and 0.85 (95 percent CI, 0.82‒0.89) for healthy LCD.

The aHRs when comparing LFD scores were 0.93 (95 percent CI, 0.89‒0.98) for overall LFD, 0.94 (95 percent CI, 0.90‒0.98) for animal LFD, 0.87 (95 percent CI, 0.83‒0.91) for vegetable LFD, 1.12 (95 percent CI, 1.07‒1.17) for unhealthy LFD, and 0.87 (95 percent CI, 0.83‒0.91) for healthy LFD.

“The healthy versions of the LCD and LFD patterns were also linked to lower triglycerides, higher high-density lipoprotein cholesterol, and lower high-sensitivity C-reactive protein levels, as well as favourable metabolomic profiles, including increased 3-indolepropionic acid and decreased valine,” the authors said. “Unhealthy patterns showed opposite associations.”

Furthermore, the authors developed multimetabolite scores of LCD and LFD indices in the LVS (r, 0.57‒0.68) and replicated in NHS, NHSII, and HPFS (r, 0.21‒0.38). They observed associations with CHD risk consistent with those based on FFQ assessments.