Keith · Journal of the National Medical Association 2011 · cross-sectional survey · n=3100

The prevalence of self-reported lactose intolerance and the consumption of dairy foods among African American adults are less than expected.

Cited 45 times in the scientific literature.

Level 4 - case-series / case-control

Cross-sectional self-reported survey

PubMed 21329245 · doi:10.1016/s0027-9684(15)30241-8 · record verified 2026-08-31

What was done

An online survey matched to the 2000 US Census assessed the self-reported prevalence of lactose intolerance and dairy intake patterns in a nationally representative sample of 2,016 African American adults and a comparison sample of 1,084 adults from the general population. Proportions were evaluated with pairwise t-tests at a 95% confidence level.

What was found

African Americans were more likely to consume fewer dairy foods, experience discomfort after intake, and believe they were lactose intolerant. Among African Americans, 49% reported ever experiencing some type of physical discomfort after consuming dairy, and 24% believed they were lactose intolerant. Of those who believed they were lactose intolerant, 85% indicated they would consume more dairy products if symptoms could be avoided. Specific comparative numbers for the general population were not reported in the abstract.

Why it matters

Self-reported lactose intolerance in African Americans (24%) was lower than historically assumed rates, suggesting that dairy avoidance may reflect perceived risk, habits, or cultural factors in addition to physiological malabsorption.

Limits

The study relied completely on self-reported survey data without objective physiological verification of lactase deficiency or malabsorption. Specific numerical values for the general population comparison group were omitted from the abstract.

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