Researchers from Edith Cowan University in Australia have arrived at conflicting conclusions regarding the impact of dietary nitrates on cognitive health. It was discovered that these compounds derived from vegetables decrease dementia risks, whereas nitrates found in drinking water and processed meat, conversely, increase them. The authors of the study reported these findings in the journal Alzheimer’s & Dementia (A&D).
The investigation involved over 54,000 adults, with their health status monitored for nearly three decades. Experts tracked the participants’ diets, focusing primarily on the intake of nitrates and nitrites, which are salts of nitric acid.
In small quantities, these substances pose no threat to the body, becoming harmful only upon accumulation. Nitrites and nitrates interact with hemoglobin to form methemoglobin, which is incapable of transporting oxygen. The consequence is a reduction in the blood’s oxygen-carrying capacity and the onset of hypoxia (oxygen starvation). When nitrates and nitrites accumulate in the intestines, carcinogenic compounds are generated.
The study demonstrated that individuals whose primary intake of nitrates came from vegetables encountered dementia less frequently. However, when water and meat products were the main sources of nitrates, an elevated risk of cognitive impairment was observed. The correlation was most pronounced with water, even when the impurity levels were minimal.
The authors suggest reasons why vegetables do not exert the same strong negative effect. They contain antioxidants and vitamins that assist in converting nitrates into nitric oxide, which supports vascular health and blood supply to the brain. Water, on the other hand, lacks these beneficial substances, while processed meat contains compounds with opposing detrimental effects.
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