Top Things to Know: Dietary Cholesterol and Cardiovascular Risk
Published: December 16, 2019
- Older adults admitted to cardiac intensive care units (CICU) face age-related cardiovascular (CV) risks and associated geriatric syndromes, including delirium and cognitive impairment, frailty, multimorbidity and polypharmacy.
- While the mean cholesterol intake in U.S. adults (≥ 20 years) according to the 2013-2014 National Health and Nutrition Examination Surveys (NHANES) was 293 mg/day, there are racial/ethnic and differences; Mexican-Americans have the highest intake with a mean of 338 mg/day, while the intake for non-Hispanic blacks and whites is 320 mg/day and 282 mg/day respectively. Mean intake in women was 242 mg/day and 348 mg/day in men.
- In descending order, the major contributors of dietary cholesterol were meat (including poultry, mixed dishes, red meat, processed meat and seafood), eggs, grain products and full-fat dairy products. On average, meat contributed 42% of total cholesterol intake and eggs contributed 25% of total cholesterol, while other food groups contributed the additional third.
- Of the 17 observational studies included, 12 reported no significant association between stroke, coronary heart disease (CHD) events or CHD death and dietary cholesterol, regardless of the dietary assessment method (food frequency questionnaires, 24 hour dietary recall, or 24 hour food diaries); positive associations in others were attenuated, when adjusted for energy intake, or other dietary components such as fiber or saturated fat.
- The meta-analyses of observational studies conducted prior to December 2013 summarized that the majority of published studies did not identify a significant positive association between dietary cholesterol (including egg intake) and CVD risk; specifically, egg intake was not significantly associated with stroke and CHD. However, two studies showed that a greater than one egg a day was associated with 20-30% higher risk of heart failure compared with infrequent egg intake in men, but not in women.
- The advisory suggests that interpreting results from observational studies examining the relationship between dietary cholesterol and CVD risk is challenging. Evidence is inconsistent and the discrepant results are likely due to residual confounding. Randomized controlled trials that distinguish between the effect of dietary cholesterol, per se, and the effect of dietary patterns high in cholesterol or saturated fat, are included.
- A meta-analysis of 17 intervention trials that ranged from 4-12 weeks reported an increase in total cholesterol (11.2 mg/dL), LDL-cholesterol (6.7 mg/dL), and HDL-cholesterol (3.2 mg/dL) concentrations in the intervention group compared with the control group. Results from a meta-analyses of 55 randomized, controlled dietary intervention studies suggest that dietary cholesterol is directly associated with LDL-cholesterol concentration, and this relationship persists after adjustment for dietary fat type.
- LDL cholesterol concentration is a stronger predictor of CVD risk than total cholesterol. In the context of eating patterns, replacing saturated fat with unsaturated fat as well as improving saturated fatty acid to polyunsaturated fatty acids (PUFA) ratio will lower LDL-C more than dietary cholesterol alone.
- Rather than focus on a single nutrient, the advisory emphasizes dietary patterns that are low in saturated fat intake and include healthy fats from liquid non-tropical vegetable oils (which do not contain cholesterol) and characterized by fruits, vegetables, whole grains, low-fat or fat-free dairy products, lean protein sources, nuts and seeds. Plant-based protein sources can further decrease dietary cholesterol intake.
- The advisory clarifies that healthy individuals can include up to one whole egg or equivalent daily, provides caveats for patients with dyslipidemia, and those with diabetes or at risk for heart failure. It suggests that older patients limit consumption to one or two eggs per day.
Citation
Carson JAS, Lichtenstein AH, Anderson CAM, Appel LJ, Kris-Etherton PM, Meyer KA, Petersen K, Polonsky T, Van Horn L; on behalf of the American Heart Association Nutrition Committee of the Council on Lifestyle and Cardiometabolic Health; Council on Arteriosclerosis, Thrombosis and Vascular Biology; Council on Cardiovascular and Stroke Nursing; Council on Clinical Cardiology; Council on Peripheral Vascular Disease; and Stroke Council. Dietary cholesterol and cardiovascular risk: a science advisory from the American Heart Association [published online ahead of print December 16, 2019]. Circulation. doi: 10.1161/CIR.0000000000000743.