Quebec study finds many seniors may have a vitamin B12 deficiency

Many seniors may unknowingly be suffering from a vitamin B12 deficiency, a new Quebec study warns.

The problem could be easily solved, however, simply by increasing the consumption of dairy products beyond what is currently officially recommended.

"We wanted to see what the association is between what people eat and the risk of developing vitamin B12 deficiency. And what we found was really interesting," said University of Sherbrooke nutrition professor Nancy Presse.

The study involved a cohort of around 1,750 healthy elderly people who were followed for four years.

After analyzing blood and urine samples, researchers found that between 10 and 13 per cent of their subjects had a vitamin B12 deficiency.

"Health Canada currently recommends that seniors consume 2.4 micrograms of vitamin B12 per day," said Presse. "However, she and her colleagues have measured that it is only at 4.8 micrograms per day - twice the official recommendation - that we begin to see a marked reduction in the risk of deficiency.

"The 2.4 is really too low, everyone agrees on that," she said. "If you look at the studies and the work around the world, often we'll suggest between 5 and 10 micrograms."

In addition, Presse said, Health Canada recommends that seniors take a supplement or eat foods fortified with vitamin B12, such as soy beverages.

"The problem is that these foods are extremely rare in this country, and you don't have to take supplements or fortified foods to avoid the problem anyway," she said.

Vitamin B12 is found in animal foods such as meat, poultry, fish, seafood, eggs and dairy products. The researchers, therefore, wanted to know whether certain foods had a greater impact than others on reducing the risk of deficiency.

Since calcium is required for vitamin B12 absorption, and dairy products are rich in calcium, Presse had hypothesized that these products might have the greatest impact.

"Indeed, that's what we saw," she said. "It was the only food group that came out as having an impact on reducing the risk of impairment."

The vitamin B12 deficiency detected in between 10 and 13 per cent of the cohort is "huge," she said, and should not be so high since all subjects were healthy.

The researchers were able to link the problem to specific dietary habits. They found that an intake of about 1.6 micrograms of vitamin B12 in the form of dairy products is sufficient to induce a significant reduction in the risk of deficiency, of the order of 50-60 per cent.

"One point six micrograms is a big glass of milk, so it's easy," said Presse. "These are not huge amounts. One to two servings of dairy products a day would probably be enough to induce a marked decrease in the risk of vitamin B12 deficiency in the elderly."

And the figures may not even do justice to the true scale of the problem. When the researchers analyzed their data, they concluded that possibly no more than 30 per cent of older people consume enough vitamin B12 to avoid deficiency.

Several factors, such as medication use and aging of the stomach lining, probably explain the higher risk of deficiency in the elderly.

"We think that the needs increase, precisely as we age, because absorption is less and less efficient," said Presse. "So maybe 2.4 micrograms is okay when you're 30, but not when you're 70."

The diagnosis of vitamin B12 deficiency is usually made by taking a blood test. Initial symptoms may include tingling and loss of feeling in the extremities, as the deficiency damages the sheathing that surrounds the nerves.

The study was published in the November issue of the Journal of Nutrition, which made it the editor's choice for this issue.

This report by The Canadian Press was first published in French on Nov. 19, 2022.