Brain Food

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The oscar-winning Still Alice was a powerful film. It was heart breaking yet inspiring. Beautifully portrayed by Julianne Moore, Dr. Alice Howland was a successful and reputable linguistics professor in Columbia. She had it all – married to a loving husband John (Alec Baldwin), a respectable research physician, and had 3 beautiful children (Kate Bosworth, Hunter Parrish and Kirsten Stewart). This all changed when Alice was diagnosed with an early onset of Alzheimer's disease (阿爾茲海默氏症). The movie captures Alice’s rapid cognitive deterioration, from initial stages where she experienced tip-of-the-tongue (failure to retrieve word from memory) during a guest lecture (which was quite ironic as she was renowned in the linguistics field), got lost during a jog, to extreme memory loss, leading to her inability to do easy tasks such as finding the toilet in her own home or recognising her family members. 

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After watching the movie, the first thing that came to my mind was – how could nutrition help prevent the development of this frightening disease? This article will fill you in with the most recent findings on nutrition prevention of cognitive impairment in Alzheimer’s disease.

            Alzheimer’s disease is the most common form of dementia (認知障礙症;前稱老年痴呆症，一般稱為腦退化症), and can occur in two forms – the rare early onset that Alice had, with symptoms that develop before the age of 65, and the more common late onset, wherein first symptoms generally develop after 65. In Hong Kong, 1 in every 3 person in the elder population over 85 has dementia (1). The prevalence in individuals aged 70 years or above was 103,433 in 2009, and is estimated to increase to 332,688 in 2039 (2) - a 222% increase.

            The most extensively researched diet related to decreasing cognitive impairment is the Mediterranean diet. The food pyramid below illustrates the components and composition comprising this diet, as well as the importance of physical activity and sharing meals with family and friends. 

The Mediterranean Lifestyle. [Image Source]

Olive oil

Monounsaturated fatty acids - MUFAs, tyrosol, caffeic acid and other phenolic compounds

Fish

Omega-3 polyunsaturated fatty acids - PUFAs

Wine

Alcohol and phenolic compounds i.e. resveratrol

Fruits and vegetables

Flavonoids and vitamin C & E - antioxidants

            The incorporation of the foods above in the Mediterranean diet has been inversely associated with cognitive decline and dementia (3). Findings from two meta-analyses pooling data from observational studies (one longitudinal study (4), and the other included longitudinal, cross-sectional and case control studies (5), both concluded that the Mediterranean diet is protective against Alzheimer's Disease. 

            Guidelines are being developed to members of the public with aims to prevent Alzheimer’s disease, which are comparable to the Mediterranean lifestyle described above. These 7 guidelines were based on substantial yet inconclusive evidence of benefit, and such implementation was thought to pose no harmful risk to the public (6).

7 lifestyle guidelines suggested by Barnard et al. (6) to prevent Alzheimer's disease. [Image Source]

From the bottom, clockwise.

1.     Minimise your intake of saturated fats and trans fats. This is already the general recommendation to the public, to decrease risk of obesity and its related diseases, i.e. Type II diabetes and cardiovascular diseases.

2.     If using multi-vitamins, choose those without iron and copper, unless directed by your general practitioner.

3.     Although the role of aluminium in cognitive disorders remain are subject to debate, those who desire to minimise aluminium exposure can avoid the use of cookware, antacids, baking powder, or products that contain aluminium.

4.     Incorporate sufficient intakes of Vitamin B12 in your diet, especially for those who are vegetarians or vegans. UK recommended nutrient intake (RNI) of Vitamin B12 is 1.5 μg/d.

5.     Similar to the principles of the Mediterranean diet, vegetables, legumes (beans, peas, and lentils), fruits, and whole grains should be primary staples of the diet, replacing meats and dairy products.

6.     Dietary sources of Vitamin E should come more from food than supplements. Food sources include seeds, nuts, green leafy vegetables and whole grains. Safe Intakes of Vitamin E in the UK for men is 4 mg/day and 3mg/day for women.

7.     Include aerobic exercise in your routine. E.g. 40 minutes of brisk walking 3 times per week.

Pu erh (Pu'er - 普洱) is an example of black fermented tea frequently consumed by Chinese populations. [Image Source]

Lastly, some observational data has shown the effects of tea consumption in reducing the prevalence of cognitive impairment in a Chinese population (6). Black fermented tea and oolong tea (semi-fermented) was shown to reduce cognitive impairment when compared to green tea. Coffee, on the other hand, has shown no beneficial effects (7). Further research is required to establish the beneficial effects of tea on the prevention of Alzheimer's disease.

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Takeaways:

There are currently no established dietary guidelines for the prevention of Alzheimer's disease, but higher adherence to the Mediterranean diet has shown to decrease cognitive decline. .

Leading a healthy lifestyle by decreasing the consumption of saturated and trans fatty acid, increasing plant-based foods as well as increase physical activity to fight against developing Alzheimer's disease!

References

(1) Yu, R., Chau, P.H., McGhee, S. M., Cheung, W. L., Chan, K. C., Cheung, S. H,, Woo, J.. (2012) Trends in prevalence and mortality of dementia in elderly Hong Kong population: projections, disease burden, and implications for long-term care.
International Journal of Alzheimer's Disease 2012, 1-6.

(2) Department of Health, HKSAR. Dementia Care Seminar cum Kick-off Ceremony for Dementia Care Campaign. Available from: http://www.dh.gov.hk/english/press/2006/061013.html. Accessed on 20 April, 2014.

(3) Yannakoulia, M. Kontogianni, M., Scarmeas, N. (2015) Cognitive health and Mediterranean Diet: Just diet or lifestyle patter? Ageing Research Reviews 20, 74-78.

(4) Psaltopoulou, T., Sergentanis, T.N., Panagiotakos, D.B., Sergentanis, I.N., Kosti, R., Scarmeas, N. (2013) Mediterranean diet, stroke, cognitive impairment, and depression: a meta-analysis. Annals of Neurology 74, 580–591. 

(5) Singh, B., Parsaik, A.K., Mielke, M.M., Erwin, P.J., Knopman, D.S., Petersen, R.C., Roberts, R.O. (2014) Association of Mediterranean diet with mild cognitive impairment and Alzheimer’s disease: a systematic review and meta-analysis. Journal of Alzheimer’s Disease 39, 271–282. 

(6)  Barnard, N. D., Bush, A. I., Ceccarelli, A., Cooper, J., de Jager, C. A., Erickson, K. I., Fraser, G., Kesler, S., Levin, S. M., Lucey, B., Morris, M. C., Squitti, R. (2014) Dietary and lifestyle guidelines for the prevention of Alzheimer's disease. Neurobiology of Aging 35, Supplement 2, 74-78.

(7)  Ng, T-P., Feng, L., Niti, M., Kua, E-K., and Yap, K-B. (2008) Tea consumption and cognitive impairment and decline in older Chinese adults. American Journal of Clinical Nutrition 88(1), 224-231.