Source of nitrate matters for dementia risk, study finds

In a Danish study of over 54,000 adults followed for up to 27 years, nitrate from vegetables was linked to a lower dementia risk, while nitrate and nitrite from red/processed meat and from drinking water were linked to higher risk. The protective vegetable effect may come from antioxidants that aid nitric oxide formation and block harmful N-nitrosamines, whereas meat lacks these protections and water nitrate could form N-nitrosamines in the body. The study is observational, so it cannot prove causation, and regulators may need to re-evaluate drinking-water nitrate limits, though the overall benefits of drinking water remain.