Low vitamin D levels associated with poorer cognition in older men

Like us, guinea pigs can’t make vitamin C, but must obtain it from their diet. This makes them a good model for examining the effects of vitamin C deficiency.

The study involved 104 healthy older adults (average age 87) participating in the Oregon Brain Aging Study. Analysis of the nutrient biomarkers in their blood revealed that those with diets high in omega 3 fatty acids and in vitamins C, D, E and the B vitamins had higher scores on cognitive tests than people with diets low in those nutrients, while those with diets high in trans fats were more likely to score more poorly on cognitive tests.

A study involving 676 children (7-9) in rural Nepal has found that those whose mothers received iron, folic acid and vitamin A supplementation during their pregnancies and for three months after the birth performed better on some measures of intellectual and motor functioning compared to offspring of mothers who received vitamin A alone. However, there was no significant benefit for those whose mothers received iron, folic acid and zinc (plus vitamin A), or multiple micronutrients.

Another study has come out showing that older adults with low levels of vitamin D are more likely to have cognitive problems. The six-year study followed 858 adults who were age 65 or older at the beginning of the study. Those who were severely deficient in vitamin D were 60% more likely to have substantial cognitive decline, and 31% more likely to have specific declines in executive function, although there was no association with attention.

A study involving 236 persons with multiple sclerosis has found that only 7% of those with secondary-progressive MS showed sufficient vitamin D in their blood, compared to 18.3% of patients with the less severe relapsing-remitting type, and that higher levels of vitamin D3 and its byproducts were associated with better scores on cognitive tests (especially reasoning and planning), and less brain atrophy and fewer brain lesions. Lower-than-normal vitamin D status is known to be associated with a higher risk of developing MS

A rat study has found that increased levels of magnesium in the brain improved many aspects of learning and memory in both young and old rats. Because it is difficult to boost brain magnesium levels with traditional oral supplements, the researchers developed a new magnesium compound, magnesium-L-threonate (MgT). The cognitive improvements were associated with an increase in synapses and improved synaptic plasticity.

A review described as “definitive” has concluded that there is ample biological evidence to suggest an important role for vitamin D in brain development and function, and that supplementation for groups chronically low in vitamin D is warranted. Vitamin D has long been known to promote healthy bones, but more recently has been found to have a much broader role — over 900 different genes are now known to be able to bind the vitamin D receptor.

A guinea pig study has found that newborn guinea pigs subjected to moderate vitamin C deficiency had 30% fewer hippocampal neurons and markedly worse spatial memory than guinea pigs given a normal diet. For several reasons the neonatal brain is thought to be particularly vulnerable to even a slight lowering of the vitamin C level. Vitamin C deficiency is very common in some parts of the world, and even in wealthy nations occurs in an estimated 5-10% of the adult population.

Seventh graders given 20 mg zinc, five days per week, for 10 to 12 weeks showed improvement in cognitive performance, responding more quickly and accurately on memory tasks and with more sustained attention, than classmates who received no additional zinc. Those who received only 10mg a day did not improve their performance. Previous studies have linked zinc nutrition to motor, cognitive and psychosocial function in very young children and adults, but this is the first study of its effect in adolescents.

A theory that changes in fat metabolism in the membranes of nerve cells play a role in Alzheimer's has been supported in a recent study. The study found significantly higher levels of ceramide and cholesterol in the middle frontal gyrus of Alzheimer's patients. The researchers suggest that alterations in fats (especially cholesterol and ceramide) may contribute to a "neurodegenerative cascade" that destroys neurons in Alzheimer's, and that the accumulation of ceramide and cholesterol is triggered by the oxidative stress brought on by the presence of the toxic beta amyloid peptide.