By Willow Lawson, published on February 1, 2004 - last reviewed on June 21, 2007
What do cheese, chicken, tuna and oysters have in common? Besides being staples of high-protein diets, they are also fine sources of B12, a vitamin increasingly linked to sturdy mental health.
Over the past several years, evidence has mounted that B vitamins—B12 and folate in particular—may ward off depression and other mental problems. A Finnish study is only the latest to link B vitamins to maintenance of good mood.
It found that high levels of vitamin B12 in the bloodstream were linked to more successful outcomes among people being treated for depression. The study tracked 115 outpatients who were seeing psychiatrists and therapists as treatment for major depression. Just over half of the patients were also taking antidepressant medications. When researchers followed up with patients six months after counseling sessions had ended, people whose B12 levels were highest had had the most success in halting depressive symptoms.
Scientists haven't pinpointed the mechanisms in the brain that account for these benefits. But they have some made some connections that show B vitamins are crucial to balanced brain chemistry and mood.
Bs are necessary for the basic upkeep of nerve and blood cells, often the result of complex biochemical brain reactions. B12 and folate, or folic acid, helps rid the body of homocysteine, a byproduct of protein metabolism that is also linked to heart disease and stroke. B vitamins are also essential ingredients for the production and proper functioning of several neurotransmitters including dopamine, crucial to the experience of pleasure.
But that's not all. A deficiency of B12, or cobalamin, is also known to cause delays of motor and language skills in children. In 2003, the Centers for Disease Control and Prevention warned that children breastfed by vegan mothers, who don't eat any animal products, could be in danger of B12 deficiency.
The Finnish researchers suggest that vitamin B12 deficiency may lead to build up of homocysteine in the blood, which studies show may exacerbate depression. Bs are also needed to help convert carbohydrates—the only food the brain can use—to energy. They even synthesize immune system antibodies.
What can cause a deficiency of B12? The good news is that B12 is found in meat, chicken and fish as well as other animal products like cheese and eggs. Vegetarian foods and breakfast cereals are often supplemented with B12.
Eating a well-balanced, nutritious diet is always in order to boost one's mental and physical energy, but this may be especially difficult for people suffering from depression. So the blues themselves may be a culprit in vitamin deficiency. "Depression may affect the quality of food in the diet," according to Jukka Hintikka, a researcher at Kuopio University Hospital in Finland and the lead researcher of the study.
Poor appetite and diet often accompany depression and easily lead to low levels of B12 and especially folate, a nutrient with a well-established link to mood. While many of us reach for carbohydrates and fats to ease stress, these foods may provide only momentary comfort. In the long run they can contribute to the core problem.
The symptoms of B12 deficiency may be vague—lethargy, short attention span, reduced motivation. Extreme symptoms can range from mild confusion and irritability to hallucinations, depression, memory loss and paranoia. And many of these symptoms could be related to a deficiency other than vitamin B12.
The lack of other vitamins, such as B1, B2, B6 and C, can generate feelings of irritability and depression. They are found in abundance in fruit, brown rice, broccoli, wheat germ, brussels sprouts and collard greens. However, no one food has all of the B vitamins, so a varied diet is essential.
When in doubt, researchers say it can't hurt to pop a multivitamin.