Researchers recruited 225 hospitalized acutely ill older adults with an average age of 76 to take a 400 milliliter oral multi-vitamin supplement per day or a placebo along with a normal hospital diet for six weeks. The multi-vitamin provided 100% of the UK Reference Nutrient Intake for healthy older persons and about 1,000 calories. After six weeks, those in the multi-vitamin group had significantly increased levels of folate in red blood cells and vitamin B12 in blood plasma, while these nutrients decreased in the placebo group. Researchers noted that many studies have linked low folate and vitamin B12 to depression. “Both folate and vitamin B12 are important for the nervous system at all ages,” they said, “but in older people where deficiencies are known to be common even in relatively healthy persons, low folate and vitamin B12 status affects mood, cognitive and social functions.”
At six months, those in the multi-vitamin group reported significantly better depression test scores compared to placebo. Scientists observed that depression test scores in the multi-vitamin group improved regardless of whether participants had reported mild or severe depression at the start of the study or had not been depressed at all. “Improvement of micronutrient [vitamin and mineral] status would be the most plausible explanation for the results,” researchers stated. In discussing the reasons for the study, the authors noted that there is little research on the effects of nutritional supplements on mental health in older adults.