Table 1.

Randomized Controlled Trials of Dietary Interventions and their Effects on Cognitive Function

First Author	Year	Sample	Dietary Component	Length of Follow-up	Conclusions
Yehuda	1996	100 adults with probable AD	n-3 and n-6 fatty acids	4 weeks	Modest improvement in short-term memory and quality of life
Chiu	2008	46 adults with MCI or AD	n-3 fatty acids	24 weeks	Improvement in clinician rating of cognitive function
Terano	1999	20 elderly adults with VaD	DHA supplementation	1 year	Modest improvement in MMSE and Hasegawa’s dementia rating scale after 6 months, but no group differences after 1 year
van de Rest	2008	321 healthy adults ≥ 65 years of age	EPA + DHA	26 weeks	No group differences
Freund-Levi	2006	204 adults with AD	n-3 fatty acids	6 months	No group differences with only modest improvements among a subgroup of mildly impaired patients
Sano	1997	341 patients with moderate AD	Selegiline or alpha-tocopherol (vitamin e)	2 years	Slowed rates of cognitive decline in treatment group relative to placebo
Petersen	2005	769 patients with MCI	Vitamin E supplements or Donepezil	3 years	Both treatments showed slower rates of conversion to AD during the first year and this effect was most pronounced among individuals with the APOE-4 genotype. No group differences after 3 years
Balk	2007	Meta-analysis of 14 RCTs	B6, B12, and Folate	Range: 5 weeks – 1 year	Equivocal findings across a range of doses and administrations
Malouf & Grimley	2008	Meta-analysis of 8 RCTs	Folate supplementation with and without B12	Range: 2–3 years	No evidence that increasing folate and B12 levels improves cognitive function
Malouf & Areosa	2003	Meta-analysis of 3 RCTs	B12	Range: 3 months – 1 year	No evidence that increasing B12 improves cognitive function
Malouf & Grimley	2003	Meta-analysis of 2 RCTs	B6	Range: 12 weeks – 1 year	No evidence that increasing B6 levels improves cognitive function
Kang	2008	2,009 women > 65 years of age with cardiac disease	B6, B12, and folic acid	5.5 years	No overall group difference. Subgroup analyses showed that women with low B vitamin levels exhibited preserved cognitive function relative to controls
Witte	2009	50 normal or overweight, older adults	Caloric restriction or unsaturated fatty acids	3 months	Caloric restriction increased verbal memory and these improvements were correlated with decreased levels of fasting insulin and C-reactive protein
Martin	2007	48 overweight adults, aged 25 – 50 years	Caloric restriction with or without exercise and a low-calorie diet	6 months	No change in cognitive function
Halyburton	2007	93 overweight or obese adults	Low-carbohydrate, high-fat diet	8 weeks	No clinically significant change in cognitive function