Nitrates from vegetables—especially leafy greens and beets—are generally beneficial, due to their synergistic effects with antioxidants and other protective compounds. In contrast, nitrates in processed meats can form harmful byproducts during cooking or digestion and are linked to higher risks of chronic disease. A recent study found that people who eat more nitrate from vegetables show fewer signs of early brain changes associated with Alzheimer’s.

Researchers analyzed data from more than 500 cognitively healthy older adults living in Australia. They estimated nitrate intake from food frequency questionnaires. They tracked the participants' brain health over 10 years using two types of brain scans: one to detect beta-amyloid buildup—a hallmark of Alzheimer's—and one to monitor brain shrinkage. They used statistical models to determine whether nitrate intake from different food sources affected brain changes, and whether results differed by sex or by presence of the APOE4 gene variant, which increases Alzheimer’s risk.

Among women who carried the APOE4 gene variant, those with the highest intake of plant-sourced nitrate accumulated beta-amyloid at about half the rate of those with lower intakes. They also experienced slower shrinkage of the right hippocampus, a region critical for memory. Moderate plant nitrate intake also appeared protective in men with the gene variant and those without it, but the patterns varied depending on sex and genetic risk.

These findings suggest that nitrate from vegetables helps protect brain health in older adults, particularly those at higher genetic risk for Alzheimer’s disease. The link appeared strongest for markers of beta-amyloid buildup and was less consistent for brain volume loss. Learn about other lifestyle strategies for reducing Alzheimer’s disease risk in this episode featuring Dr. Dale Bredesen.