Welcome to part 4 of our series highlighting the science-backed benefits of 11 essential nutrients! Similar to our previous articles, we will delve into the emerging evidence linking these nutrients to optimal cognitive function, with a focus on women’s brain health. We will discuss which foods serve as rich sources of these nutrients so that you can find new recipes to incorporate them into your healthy, balanced diet.

This brings us to our third member of the B-family of vitamins, Vitamin B9. Otherwise known as folate, Vitamin B9 is a water-soluble vitamin with substantial impacts on human health. You may recognize this vitamin as a key component found in prenatal supplements. This essential nutrient plays a crucial role in DNA synthesis and repair, which during pregnancy, is occurring at a much higher rate to support fetal growth. 

The role of folate in supporting growth of the brain and spinal cord during pregnancy is well-documented, but the brain benefits of vitamin B9 extend beyond infancy. This essential B vitamin is vital for the synthesis of nucleotides, the building blocks of DNA. Consequently, folate has a direct impact on the development of the brain and the synthesis of neurotransmitters that allow brain cells to communicate with one another effectively. 

Like other B vitamins, folate is an essential nutrient, meaning it must be obtained through one’s diet as the human body cannot synthesize it. 

Fortunately, there are various natural sources of folate to help meet the recommended daily intake. Some of the most folate-rich foods include leafy greens, legumes, citrus fruits, and animal products, such as lean meats. Fortified foods, such as breakfast cereals and grain products, are also common sources of folate, a form of the vitamin that is often added to food products.

The human brain relies heavily on the synthesis and maintenance of neurotransmitters, such as serotonin, dopamine, and norepinephrine, to regulate mood, emotions, and cognition. Folate is a key player in this process, as it is involved in the conversion of the amino acid homocysteine into methionine, which is essential for neurotransmitter production. 

Low levels of folate can lead to elevated homocysteine levels, which have been associated with cognitive impairment and an increased risk of neurodegenerative diseases. 

In addition to its role in DNA synthesis, folate is also involved in the modification of a protein called tau – which is predominantly found in brain cells. Tau proteins in the brains of people with Alzheimer’s disease (and certain other types of dementia) are misfolded and abnormally shaped. 

A 2021 review article by Zhang et al. published in the journal Frontiers in Neuroscience synthesized the large body of evidence linking dietary folate intake to prevention of disease. The authors note that low folate levels were associated with an increased relative risk of all types of dementia, including vascular and Alzheimer’s forms of dementia. On the flip side, they also demonstrated that sufficient daily intake of folate was a protective factor against the development of Alzheimer’s disease. 

Additionally, adequate intake of vitamin B9 is associated with improved cognitive function. 

Studies have shown that individuals with higher folate levels tend to have better memory, attention, and processing speed. A 2019 article published in Current Alzheimer’s Research provides further evidence linking folate supplementation with improved cognitive function. The authors recruited 240 participants with mild cognitive impairment and randomized them to receive either a vitamin B supplement (containing Vitamin B9 and B12) or a placebo pill for 6 months. 

After the completion of the study, the participants underwent rigorous testing of their memory and attention, and also had lab work to measure inflammatory markers in the blood. Compared with the placebo group, those who received the supplement had lower levels of homocysteine and other inflammatory markers. 

Additionally, there was a significant improvement in cognitive test results. Taken together, these study results demonstrate the positive therapeutic effects of folate on cognition and memory – amongst both healthy adults and those with mild cognitive impairment. 

From brain development during pregnancy to cognitive function and neuroprotection throughout life, folate plays a critical role throughout our lifespan. As our understanding of the brain benefits of vitamin B9 continues to evolve, it underscores the importance of a diet rich in this essential nutrient for optimal brain health and function.


Part 1: Vitamin A (to Zinc!)

Part 2: Vitamin B1 (Thiamine)

Part 3: Vitamin B2 (Riboflavin) 

Part 4: Vitamin B9 (Folic Acid)