Scientists have developed a new evidence-based scale that rates animal and plant-based foods that improve depressive symptoms.
There is increasing evidence regarding the crucial role that diet plays in brain health, particularly in the areas of depression and dementia, said Drew Ramsey, MD.
“The data are very clear that there’s a powerful prevention signal when we help our patients eat better.”
Plant foods are high on Dr Ramsey’s brain food scale. To develop this nutrient profiling system, he and his colleagues assessed the literature and compiled a list of what they call brain essential nutrients (BEN) that affect the treatment and prevention of depression.
Key nutrients include long-chain omega 3 fatty acids, magnesium, calcium, fiber, and vitamins B1, B9, B12, D, and E.
They then gathered nutritional data for top food sources of BEN from the Agricultural Research Service Nutrient Data Laboratory and used a formula to calculate the Brain Food Scale score.
“We were very interested in using the scientific literature to winnow down the key nutrients that have evidence that they are very, very involved in depression,” said Dr Ramsey.
In addition to plant sources of these nutrients, they wanted to include animal sources, because some nutrients, such as vitamin B12, are predominantly found in meat and other animal products and are “absolutely critical for brain health,” said Dr Ramsey.
Possible mechanisms by which these foods may boost brain function include neuronal membrane stabilization and anti-inflammatory effects.
Although these nutrients are key to brain function, 2009 statistics from the US Department of Agriculture show that most Americans are not getting enough of them. For example, the percentages of the US population that do not meet the recommended daily allowances for these key nutrients are as follows:
- Vitamin E: 86%
- Folate: 75%
- Calcium: 73%
- Magnesium: 68%
- Zinc: 42%
- Vitamin B6: 35%
- Iron: 34%
- Vitamin B12: 30%
In addition to leafy green vegetables, researchers highlighted the importance of organ meats, game meats, nuts (pecans, walnuts, and peanuts), bivalves (mussels, clams, oysters), mollusks (octopus, squid, snail), and fish (salmon and sardines). Although it is recommended that patients eat 8 to 12 ounces of fish a week, it is important to choose fish that are lower in mercury. Individuals should therefore limit consumption of shark and swordfish
Dr Reynolds also stressed that he wants to help patients make better choices when it comes to meat. Those choices, he said, should include grass-fed and pastured animals.
Although the research focuses more in the areas of depression and dementia, new trials are looking at attention-deficit/hyperactivity disorder, anxiety, and addictions, said Dr Reynolds.
The study includes 176 patients with major depressive episodes at two centers in Victoria, Australia. Participants were randomly assigned to either a dietary intervention group, which focuses on advocating a healthy diet, or a social support group.
Although results of this trial likely will not be published until later this year, Dr Ramsey’s group has had a chance to discuss the results with its investigators, and the results are “positive” and “better than expected.”