Vitamins, DHA, and the aging brain
It is known that a Western diet is associated with dementia – the risk factors for Alzheimer’s disease are almost identical to those for cardiovascular disease.1 In contrast, higher vegetable and fruit intake is associated with decreased risk of cognitive decline and dementia.2,3
Vitamins are essential for thousands of chemical reactions in the body, and certain vitamins and other phytochemicals have been singled out for their critically important functions in the brain. These include B vitamins, vitamins C, D, and E, and omega-3 DHA.
- Vitamin B1 is needed in order for the brain to utilize glucose for energy
- Folate is crucial during early brain development and is important for memory
- Vitamin B12 is important for memory and production of neurotransmitters, and deficiency in B12 can cause nerve injury leading to impaired sensation and even blindness.4 Higher B12 blood levels are associated with slowed cognitive decline.5
- Vitamin B6 is also involved in neurotransmitter production, and deficiency is associated with seizures, chronic pain, and depression.6
Antioxidant Vitamins C and E
- The brain is highly susceptible to oxidative stress, which is one of the main mechanisms of brain aging and a contributing factor to neurodegenerative conditions.7,8
- Nerve endings have highest concentrations of vitamin C found in the human body. Vitamin C is thought to function largely as an antioxidant in the brain and nervous system. Blood levels of vitamin C have been positively associated with IQ.4
- Vitamin E is a component of brain cell membranes, and along with vitamin A and carotenoids, protects vulnerable unsaturated fatty acids (like omega-3s) from oxidative damage. Low vitamin E status is associated with greater risk of Alzheimer’s disease.4
- Vitamin C and E intake were associated with higher cognitive scores in the elderly, and the association was stronger for food sources compared to supplement sources.9
- In addition to vitamin intake, polyphenols and other antioxidants present in plant foods are thought to contribute to protecting the brain from oxidative damage.4
- Vitamin D is involved in regulating glucose and calcium transport to and within the brain, and may also protect cognition by reducing inflammation and increasing availability of certain neurotransmitters.4
- Vitamin D is also involved in memory formation.10 Several studies have associated vitamin D deficiency with increased risk of cognitive impairment or dementia in older adults.11,12
- More than half of the brain consists of fat; DHA is the most abundant fat in the brain and a crucial structural component of cell membranes.13
- DHA supplements have been shown to produce learning and memory improvements in subjects who already were exhibiting mild cognitive impairment, however, a similar study in Alzheimer’s patients showed no benefit.14-16 The message from these studies is that DHA is effective when taken preventively.
Effects of vitamins and DHA on brain shrinkage in the elderly
Compared to older individuals with normal cognition, those with dementia have significantly smaller brain volumes as measured by MRI.17 A recent study analyzed blood fats and micronutrients with regard to MRI measures of brain volume and cognitive function tests in older adults. The researchers found three patterns of nutrient status that correlated to brain volume and cognitive function:
- Higher levels of vitamins B, C, D, and E – associated with greater cognitive function scores and brain volume. This pattern primarily reflected fruit and vegetable intake.
- Higher levels of omega-3 fatty acids (DHA) – associated with greater cognitive function scores and brain volume. This pattern primarily reflected fish intake.
- High levels of trans fats – associated with lower cognitive function scores and brain volume.18,19
Protect your brain
The American diet is insufficient in providing these brain-healthy nutrients, but a nutritarian diet provides both the amount and variety of vitamins and other phytochemicals that support optimal brain function. It is especially important to eat healthfully, supplement with vitamin D, and get adequate DHA as we age, especially after age 50. Keep in mind that fish is not an ideal source of DHA, since mercury is toxic to the brain and reduces the body’s antioxidant status.20-23 An algae-based DHA supplement is a healthful, environmentally friendly source of beneficial omega-3 fatty acids. Eating plenty of unrefined plant foods and taking a non-fish source of DHA, such as my DHA Purity starting early in life will allow us to maintain valuable vitamins, omega-3s, and other phytochemicals in brain tissue to keep our minds sharp as we age.
1. Fillit H, Nash DT, Rundek T, et al: Cardiovascular risk factors and dementia. Am J Geriatr Pharmacother 2008;6:100-118.
2. Morris MC, Evans DA, Tangney CC, et al: Associations of vegetable and fruit consumption with age-related cognitive change. Neurology 2006;67:1370-1376.
3. Hughes TF, Andel R, Small BJ, et al: Midlife fruit and vegetable consumption and risk of dementia in later life in Swedish twins. Am J Geriatr Psychiatry 2010;18:413-420.
4. Bourre JM: Effects of nutrients (in food) on the structure and function of the nervous system: update on dietary requirements for brain. Part 1: micronutrients. J Nutr Health Aging 2006;10:377-385.
5. Tangney CC, Tang Y, Evans DA, et al: Biochemical indicators of vitamin B12 and folate insufficiency and cognitive decline. Neurology 2009;72:361-367.
6. Malouf R, Grimley Evans J: The effect of vitamin B6 on cognition. Cochrane Database Syst Rev 2003:CD004393.
7. Aliev G, Smith MA, Seyidov D, et al: The role of oxidative stress in the pathophysiology of cerebrovascular lesions in Alzheimer's disease. Brain Pathol 2002;12:21-35.
8. Barja G: Free radicals and aging. Trends Neurosci 2004;27:595-600.
9. Wengreen HJ, Munger RG, Corcoran CD, et al: Antioxidant intake and cognitive function of elderly men and women: the Cache County Study. J Nutr Health Aging 2007;11:230-237.
10. McCann JC, Ames BN: Is there convincing biological or behavioral evidence linking vitamin D deficiency to brain dysfunction? The FASEB Journal 2007;22:982-1001.
11. Grant WB: Does vitamin D reduce the risk of dementia? Journal of Alzheimer's disease : JAD 2009;17:151-159.
12. Llewellyn DJ, Lang IA, Langa KM, et al: Vitamin D and Cognitive Impairment in the Elderly U.S. Population. J Gerontol A Biol Sci Med Sci 2010.
13. Chang CY, Ke DS, Chen JY: Essential fatty acids and human brain. Acta Neurol Taiwan 2009;18:231-241.
14. Yurko-Mauro K, McCarthy D, Rom D, et al: Beneficial effects of docosahexaenoic acid on cognition in age-related cognitive decline. Alzheimers Dement 2010.
15. DHA Improves Memory and Cognitive Function in Older Adults, Study Suggests. 2010. ScienceDaily. http://www.sciencedaily.com/releases/2010/11/101108151346.htm. Accessed December 23, 2010.
16. Quinn JF, Raman R, Thomas RG, et al: Docosahexaenoic acid supplementation and cognitive decline in Alzheimer disease: a randomized trial. JAMA 2010;304:1903-1911.
17. He J, Iosif AM, Lee DY, et al: Brain structure and cerebrovascular risk in cognitively impaired patients: Shanghai Community Brain Health Initiative-pilot phase. Arch Neurol 2010;67:1231-1237.
18. Bowman GL, Silbert LC, Howieson D, et al: Nutrient biomarker patterns, cognitive function, and MRI measures of brain aging. Neurology 2011.
19. Diet Patterns May Keep Brain from Shrinking. 2011. American Academy of Neurology. http://www.aan.com/press/index.cfm?fuseaction=release.view&release=1010. Accessed
20. Huskies lend insight into mercury risk. 2011. EurekAlert! http://www.eurekalert.org/pub_releases/2011-11/iop-hli111711.php. Accessed
21. Oken E, Radesky JS, Wright RO, et al: Maternal fish intake during pregnancy, blood mercury levels, and child cognition at age 3 years in a US cohort. Am J Epidemiol 2008;167:1171-1181.
22. Aschner M, Aschner JL: Mercury neurotoxicity: mechanisms of blood-brain barrier transport. Neurosci Biobehav Rev 1990;14:169-176.
23. Aschner M, Walker SJ: The neuropathogenesis of mercury toxicity. Mol Psychiatry 2002;7 Suppl 2:S40-41.