Higher blood levels of three carotenoids – lutein, zeaxanthin and cryptoxanthin – in middle-aged people are associated with a lower risk of developing a form of dementia over the years. The study in Neurology

What this article is about

• Numerous studies show that antioxidants can counteract neurodegeneration
• A recent study published in Neurology shows that high blood levels of the carotenoids lutein, zeaxanthin and cryptoxanthin are correlated with a lower risk of developing dementia
• Further research will be needed to establish whether supplementing them could play a role in preventing these conditions, including Alzheimer’s

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What was discovered?

Some antioxidants could play an important role against dementia. A US research group, which includes the National Institute on Aging, has in fact shown that in middle age higher blood levels of certain antioxidants are associated with a lower risk of developing one of the various forms of dementia in the future, including Alzheimer’s. The substances in question are three carotenoids – lutein, zeaxanthin and cryptoxanthin – and the results of the study are published in Neurology.

What role do antioxidants play?

Antioxidants counteract the formation of oxygen radicals, that is, free radicalsA free radical is a particularly reactive molecule or atom that contains at least one odd electron in its outermost orbital. Because of this chemical characteristic, free radicals are highly unstable and try to return to equilibrium by stealing from the nearby atom the electron needed to equalize its electromagnetic charge. This mechanism gives rise to new unstable molecules, triggering a chain reaction that, if not stopped in time, ends up damaging cellular structures and metabolic processes.. These chemical by-products can be dangerous because they underlie degenerative processes and possible cell damage, which in turn can lead to the development of numerous diseases. Several studies suggest that antioxidants have a protective role against neurodegeneration. Against this background, the US researchers set out to study the possible relationship between the levels of certain specific molecules in our body and the risk of dementia.

How was the study conducted?

The authors involved almost 8,000 participants aged 45 and over, who underwent a general clinical checkup and the measurement of certain antioxidants in the blood. Starting from this first test, the observation period lasted on average 16 years.

Some foods containing the carotenoids investigated in the study: lutein, zeaxanthin and cryptoxanthin

Within the group, the incidence of cases of all forms of dementia detected over the entire course of the study was lower for people who had higher levels of lutein and zeaxanthin considered together. Beta-cryptoxanthin (or simply cryptoxanthin) also proved potentially protective, even when considered on its own: once again, in fact, as the blood level of the substance increased, the risk of dementia decreased.

Where are these antioxidants found?

Lutein and zeaxanthin are found in green vegetables such as cabbage, broccoli, spinach, peas and leafy vegetables, while cryptoxanthin is found mainly in certain fruits, such as oranges, papaya, mandarins and persimmons. But what about possible supplementation? “Further studies are needed to assess whether supplementation with these antioxidants can protect against dementia,” commented one of the authors of the research, May A. Beydoun of the US National Institutes of Health, recalling that “prolonging cognitive performance is a public health challenge”. This applies overseas as well as in Italy, where more than one million people currently live with dementia (according to estimates by the Istituto Superiore di Sanità), 600,000 of whom have Alzheimer’s.