Source of Nitrate Matters More Than Amount Consumed, Study Finds - Video

Vegetable Nitrates May Protect the Brain, While Meat and Water Nitrates Could Raise Dementia Risk. Not all dietary nitrates are created equal when it comes to brain health, according to new research from the Danish Diet, Cancer and Health Cohort Study published in Alzheimer’s & Dementia.

The study suggests that nitrates from vegetables may lower dementia risk, while those from animal sources and tap water could increase it.

Dietary nitrates are found in plant foods like leafy greens and root vegetables, naturally occurring animal foods, processed meat products, and even tap water. In the body, nitrates convert to nitrites and nitric oxide, a molecule that can improve blood vessel function and potentially protect the brain. However, nitrates can also form N-nitrosamines, compounds linked to cancer and possibly neurotoxicity, particularly when consumed with red meat.

The study followed 54,804 dementia-free adults over up to 27 years. Participants’ nitrate intake was assessed via food-frequency questionnaires. During follow-up, 4,750 people developed dementia, including 191 early-onset cases. Higher plant-sourced nitrate intake was linked to a 10% lower risk of dementia, with doubling of vegetable nitrate intake reducing risk by 8%. Conversely, nitrates and nitrites from animal foods and meat additives were associated with a 11–13% higher risk of dementia, while higher tap water nitrate intake correlated with a 12–16% increased risk.

Early-onset dementia appeared more sensitive to nitrate source, showing even stronger associations, though case numbers were small. Polyphenols and vitamin C, present in plant foods, may help counteract harmful nitrosamine formation from animal sources.

The researchers caution that plant-sourced nitrate intake may reflect overall healthier lifestyle and diet patterns, and the observational design cannot establish cause and effect. Yet the findings highlight a potentially modifiable factor in brain health.

Key takeaway: Prioritizing vegetables for nitrate intake, while moderating processed meats and monitoring water quality, may be a simple but meaningful strategy to support long-term cognitive health.

REFERENCE: Bondonno, C. P., Pokharel, P., Erichsen, D. W., et al. (2026). Source-specific nitrate intake and incident dementia in the Danish Diet, Cancer and Health Study. Alzheimer’s & Dementia. DOI: https://doi.org/10.1002/alz.70995. https://alz-journals.onlinelibrary.wiley.com/doi/10.1002/alz.70995