Healthy diet, depression and quality of life: A narrative review of biological mechanisms and primary prevention opportunities

Table 2 Summary of the effects of various nutrients, food groups, dietary patterns and lifestyle on prevalent or incident depression

Dietary components	Total/number of cases	mean follow-up t (yr)	Main Results1 [comparisons between quantiles (q) or the designated categories]
Cohort studies
Nutrients
Omega-3 fatty acids[6]	7903/512	2.4	q4 vs q1: OR (95%CI) 0.65 (0.47–0.90). P for trend = 0.376
Trans fatty acids[37]	12059/657	6.1	q5 vs q1: 1.42 (1.09-1.84); P for trend = 0.003
MUFA[37]	12059/657	6.1	q5 vs q1: 0.80 (0.62-1.03); P for trend = 0.05
PUFA[37]	12059/657	6.1	q5 vs q1; 0.76 (0.59-0.99; P for trend = 0.03
Magnesium[123]	12939/737	6.3	q5 vs q1: 1.11 (0.77-1.59) No association.
Nutritional adequacy[124]	13983/953	8.5	≥ 4 nutritional deficiencies vs ≤ 1: 1.37 (1.01-1.85)
Total Fiber[40]	548/198	Cross-sectional	q4 vs q1: OR = 0.54 (95%CI: 0.11–2.63); Non significant association
Foods and food groups
Fast food[125]	8964/493	6.2	q5 vs q1: 1.36 (1.02-1.81); P for trend = 0.03
Ultra-processed foods[126]	14907/774	10.3	q4 vs q1: 1.33 (1.07, 1.64); P for trend = 0.004
Baked goods[125]	8964/493	6.2	q2-5 vs q1: 1.38 (1.06-1.80);
Olive oil[37]	12059/657	6.1	q5 vs q1: 0.80 (0.62-1.04); P for trend = 0.06
Seafoods[127]	6587/1367	Cross-sectional	q3 vs q1 of fatty fish consumption: OR 0.72 (0.59–0.88). Higher intakes were non-significant
Coffee[128]	14413/199	10	≥ 4 cups/d vs < 1 cup/d: 0.37 (0.15–0.95); P for trend = 0.220
Yoghurt[36]	14542/727	9.3	Low fat: max vs min: 1.32 (1.06–1.65); P for trend = 0.001
			Whole fat: max vs min: 0.78 (0.63–0.98); P for trend = 0.02
Dietary patterns
MD score[8]	10094/480	4.4	3pts vs 0-2pts: 0.74 (0.57-0.98)
			4pts vs 0-2pts: 0.66 (0.50-0.86)
			5pts vs 0-2pts: 0.49 (0.36-0.67)
			6-9pts vs 0-2pts: 0.58 (0.44-0.77); P for trend <0.001
MD score (updated)[103]	15093/1051	8.5	q5 vs q1: 0.84 (0.69-1.02); P for trend = 0.001
Pro-vegetarian[103]	15093/1051	8.5	q5 vs q1: 0.74 (0.61-0.89); P for trend < 0.001
AHEI 2010[103]	15093/1051	8.5	q5 vs q1: 0.60 (0.49-0.72); P for trend < 0.001
DASH-Fung diet[102]	14051/410	8	< 2pts vs 3-9pts: 0.76 (0.61-0.94):
Pro-inflammatory pattern[129]	15093/1051	8.5	q5 vs q1: 1.47 (1.17, 1.85); P for trend = 0.010
Lifestyle
Mediterranean lifestyle[130]	11800/806	8.5	High vs low : 0.50 (0.32-0.81)
Healthy lifestyle score[131]	14908/774	10.4	Max vs min: 0.68 (0.49-0.95); P for trend 0.010
Alcohol[132]	13619/459	8	Moderate vs no consumption: 0.62 (0.43-0.89) in female subjects
CV risk equation[133]	16739/927	6	q5 vs q1: 3.45 (2.40-4.95) starting at 40 yr
Physical activity[7]	10381/923	6	q5 vs q1: OR (95% CI) 0.81 (0.65-1.00) P for trend < 0.01
Leisure time physical activity[134]	6343/311	10.5	> 20 METs-h/wk vs < 10 METs-h/wk; 0.84 (0.72–0.99); P for trend 0.046
Tobacco[135]	8556/190	4	Smokers vs non-smokers: 1.30 (0.97-1.73)
Childhood obesity (5 yr)[136]	11825/651	6.1	Obese vs low weight: 1.50 (1.06-2.12); P for trend = 0.012
Youth obesity (20 yr)[136]	11825/651	6.1	Obese vs low weight: 2.22 (1.20-4.08); P for trend = 0.005
Clinical trials
The PREDIMED study[119]	3923/224	5.4	MD + EVOO2 or nut supplements vs Low fat diet: multivariable adjusted 0.85 (0.64 to 1.13); Non significant associations
The MoodFOOD Study[117]	512/54	1	Multi-nutrient supplement vs placebo groups: OR = 1.06 (0.87-1.29); Non significant associations.

¹Estimates are presented as HR (95%CI) for incident depression unless stated otherwise.

²Extra virgin olive oil. MUFA: Monounsaturated fatty acids; PUFA: Polyunsaturated fatty acids; MD: Mediterranean diet.