Researchers: nutrient deficiency linked to depression, dementia

Deficiencies in nutrients, including omega-3 fatty acids, folic acid and vitamin B12, could have major consequences for the brain, according to researchers connecting nutrition, mood and cognitive function.

Joseph Hibbeln has pioneered research into the effect of the long chain polyunsaturated omega-3 fatty acids (PUFAs), EPA and DHA on mood and cognitive function. Speaking at the Food for the Brain conference in London this weekend, he described a “clear correlation” between inadequate intakes of PUFAs during pregnancy and children’s long-term mental health.

Studies had consistently shown that children whose mothers had sub-optimal levels of PUFAs were more likely to have lower IQs and behavioural problems, said Hibbeln. “We’re talking about a whole cluster of neurological problems from peer group issues to pathological behaviour. That’s a bad trajectory for kids to be on.”

There was also evidence that mothers consuming sub-optimal levels of PUFAs were more likely to suffer from post-natal depression, he added.

Many scientists now also associated elevated levels of homocysteine and correspondingly low consumption of vitamin B12 and folic acid with increased risk of dementia, he said.

It was almost impossible to reverse cognitive impairment, he continued. But folic acid and vitamin B12 supplementation could reduce the risk of developing dementia, said professor Helga Refsum, visiting professor of human nutrition at Oxford University. It could also arrest the rate of decline in those who had already developed mild forms of Alzheimer’s disease, Refsum said.

She added: “18 out of 21 published studies into this subject show a clear correlation between elevated homocysteine and dementia.” Meanwhile, severe vitamin B12 deficiency could cause the brain to atrophy and shrink.

There was strong scientific evidence linking omega-3s and brain functioning. However, it was not a foregone conclusion that EU regulators would authorise health claims about their cognitive benefits, said industry sources at the event.

Martek Biosciences’ application to make a health claim about DHA and arachidonic acid (ARA) and neural development in infants was recently rejected by the European Food Safety Authority (EFSA).

While the company’s science was strong, only two studies provided as supporting evidence related to the target group (infants aged six months to three years), said EFSA. “Only a few studies presented address the effects of DHA and ARA supplementation on neural development in infants older than six months and [only] these are considered as pertinent to the health claim.”

On the basis of the data presented, a cause and effect relationship had “not been established” between the nutrients in question and the claimed health benefit, it concluded.

However, supplementing baby foods and infant formula with DHA and ARA from six months to one year of age might benefit visual acuity maturation in infants breast-fed from four to six months of age, said EFSA.

While EFSA’s opinion was disappointing, it should not dampen confidence in using DHA in infant formula for younger babies where the science was compelling, insisted a Martek spokeswoman. “The evidence supporting use of DHA in the first six months of life is not what was on trial; this was about the age group of six months to three years.”

The tough line taken by EFSA was “potentially limiting”, she added. “But at least it shows that they are not going to let every Tom, Dick or Harry make a claim without proper scientific support. We are obviously very disappointed. But we are encouraged by EFSA’s positive comments about visual development and we are going to come back and apply for a more specific claim along these lines.”