As a nutritional psychiatrist, I always make it a point to maintain a well-balanced diet. Much of that has to do with making sure I get all the right vitamins, especially because it's essential to preventing cognitive decline.

And given that the risk of neurological diseases increases as we get older, one question I often get from my patients is: "What is the best vitamin for protecting our aging brains?"

Each of our microbiomes is like a thumbprint, so a truly effective eating plan is personalized to the unique needs of an individual. But the vitamin group I prioritize the most to keep my brain young and healthy are B vitamins.

The brain benefits of B vitamins

Depression, dementia and mental impairment are often associated with a deficiency of B vitamins, a study from the Wayne State University School of Medicine found.

"A B12 vitamin deficiency as a cause of cognitive issues is more common than we think, especially among the elderly who live alone and don't eat properly," says Rajaprabhakaran Rajarethinam, a psychiatrist and the lead author of the study.

There are eight different B vitamins, each with its own primary health benefits:

1. Increasing your energy.

Vitamin B1, or thiamin, is crucial for the basic function of our cells and the metabolism of nutrients for energy.

The brain is one of the most metabolically active organs in your body, which means it needs the support of thiamin to prevent the deficiencies that can lead to neurological problems down the line.

2. Breaking down medications.

Vitamin B2, or riboflavin, acts as an assistant to enzymes in our cells that carry out important reactions, such as in the body and brain.

It also helps to grow cells, produce energy and break down fats and external materials like medications.

3. Reducing inflammation.

Vitamin B3, or niacin, works with more than 400 enzymes to produce materials like cholesterol and fat needed within the body, and to convert energy for all our organ systems. Niacin is also an antioxidant, which helps reduce excess inflammation.

4. Supporting your overall brain health.

Vitamin B5, or pantothenic acid, is essential for making a molecular compound called coenzyme A, which helps our body's enzymes build and break down fatty acids for energy.

It also helps our cells generate acyl carrier proteins, helping to produce necessary fats. The brain is primarily fat, so pantothenic acid is among the most important vitamins in supporting brain health.

5. Fight diseases.

Vitamin B6, or pyridoxine, is notable for its role in disease prevention because proper levels of this vitamin is associated with lower risk of a number of cancers.

Additionally, pyridoxine helps many chemical reactions in the body that support immune function and brain health. 

6. Helping cells communicate better.

Vitamin B7, most commonly known as biotin, regulates cell signals for quick and efficient communication throughout the body. In the brain, it's crucial for cellular signaling via neurotransmitters.

7. Keeping you balanced.

Vitamin B9, or folate, is a popular supplement and a key vitamin for supporting brain and neurological health, optimal neurotransmitter function, and balanced psychological health.

Another benefit is that it helps encourage cellular detoxification.

8. Helping your heart.

Vitamin B12, or cobalamin, is an essential vitamin for forming red blood cells and DNA, and supporting the development and function of the nervous system.

B12 also supports the breakdown of homocysteine, a protein that can negatively impact cardiovascular health and lead to dementia when in excess.

The best Vitamin B foods

I'm a "food-first" person, so I always encourage people to incorporate foods containing these vitamins into their meals. However, our diets are not perfect, so there may be instances where supplements may help. If that's the, case my simple advice is to "test, not guess" — and consult with your doctor first.

The goods news is that B vitamins are among the easiest to work into your diet because foods that are rich in one B vitamin often contain many, if not all, of the B vitamins when consumed as whole foods.

Here are six vitamin B-rich foods I eat every day:

1. One egg contains a third of the recommended daily value of vitamin B7, while also containing small amounts of many of the other B vitamins.

2. Yogurt is high in both vitamin B2 and vitamin B12, as well as in natural probiotics, which support both gut health and mental health. I like plain Greek yogurt for the added protein.

3. Legumes such as black beans, chickpeas, edamame and lentils all help to boost your mood and brain health. They are an excellent source of vitamin B9, and include small amounts of vitamin B1, vitamin B2, vitamin B3, vitamin B5 and vitamin B6.

4. Salmon is naturally rich in all of the B vitamins, especially vitamin B2, vitamin B3, vitamin B6 and vitamin B12. Be mindful of the source of your seafood, and remember that frozen or canned salmon is a budget-friendly option, too.

5. Sunflower seeds are one of the best plant sources of vitamin B5. You can get 20% of the recommended daily value of this vitamin from just one ounce of seeds!

6. Leafy greens such as spinach, Swiss chard and cabbage are a great source of vitamin B9. This is the first food I suggest to patients who want to boost low mood.

Dr. Uma Naidoo is a nutritional psychiatrist, brain expert, and faculty member at Harvard Medical School. She is also the Director of Nutritional & Lifestyle Psychiatry at Massachusetts General Hospital and author of the best-selling book "This Is Your Brain on Food: An Indispensable Guide to the Surprising Foods that Fight Depression, Anxiety, PTSD, OCD, ADHD, and More." Follow her on Twitter and Instagram.

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