A study from Spain reports that depression could be a consequence of nutritional deficits and that there exists a link between adherence to Mediterranean, pro-vegetarian or alternative healthy index 2010 diet and reduced risk of depression.
It is a well-known fact that including fruits and vegetables in the diet improves people’s health. They are nutrient-dense, which can be used as low-calorie substitutes for calorie-heavy ingredients. This helps one consume lesser calories and potentially lose weight. Additionally, fruits and vegetables are rich in minerals, vitamins and micronutrients as well, bestowing a number of benefits and may help prevent diseases as well.
The current report enrolled 22,045 individuals for the Seguimiento Universidad de Navarra (SUN) study, which was initiated to understand lifestyle determinants of hypertension, diabetes, depression, etc. After exclusion for various reasons, 15,093 individuals were included in the study. Three diet quality scores were built- Mediterranean Diet Score (MDS), Pro-Vegetarian Dietary Pattern (PDP) and Alternative Healthy Eating Index 2010 (AHEI-2010) and participants classified as adhering to one of the three diet systems. The diet plans included some key ingredients and participants were scored based on what and how much they consumed, to arrive at their adherence scores.
The key components of the three diet plans and the criteria for a good score were:
MDS: Vegetables, fruits, nuts, cereal, fish, legumes, monosaturated to saturated fatty acid ratio, meat products, dairy products, moderate alcohol intake (moderate).
PDP: Vegetables, fruits, nuts, cereal, legumes, olive oil, potatoes, dairy, fish, eggs, added animal fats, meat and meat products.
AHEI-2010: Vegetables and fruits (≥ 4-5 servings), whole grain bread (420g/day), sugar-sweetened beverages and fruit juice (0 drinks/day), Nuts and legumes (≥ 1 serving/day), red/processed meat (0 serving/day), trans-fatty acids (≤ 0.5%), long-chain omega-3 (≥ 250 mg/day), polyunsaturated fatty acids intake (≤ 10%), sodium (lowest decile), alcohol intake (0.5-2 drinks/day for men and 0.5-1.5 drinks/day for women).
[Note: Meat and sweets were negatively scored, while nuts, fruits, and vegetables were positively scored.]
At the end of 10 years, the study subjects were requested to fill out another questionnaire, which was then compared to the one they submitted at the start of the study. Analysis of data showed:
- 1,550 participants reported being diagnosed with clinical depression (after a median follow-up of 8.5 years) and being on anti-depressant drugs.
- Moderate or high adherence to MDS, PDP or AHEI-2010 led to decreased risk of depression in the participants.
- Adherence to AHEI-2010 resulted in the greatest reduction of risk of depression.
- There was a threshold beyond which adhering to the diet plans did not offer any additional benefits, in terms of reducing the risk of depression.
The lead author of the article, Dr. Sanchez-Villegas, says to the American Association for the Advancement of Science Public Release, “We wanted to understand what role nutrition plays in mental health, as we believe certain dietary patterns could protect our minds. These diets are all associated with physical health benefits and now we find that they could have a positive effect on our mental health.”
Discussing the results further, Dr. Sanchez-Vullegas states, “Even a moderate adherence to these healthy dietary patterns was associated with an important reduction in the risk of developing depression. However, we saw no extra benefit when participants showed high or very high adherence to the diets.”
Thus, it would seem that the first step to warding off depression could be as easy as including fruits and vegetables in the diet, along with a healthy dose of legumes and nuts. Although further studies will be required to ascertain the depression-protective benefits of a vegetable/fruits/nuts/legumes- laden diet, it is a start and definitely a tastier alternative to medication.
Written by Mangala Sarkar, Ph.D.
Sánchez-Villegas, A., Henríquez-Sánchez, P., Ruiz-Canela, M., Lahortiga, F., Molero, P., Toledo, E., & Martínez-González, M. (2015). A longitudinal analysis of diet quality scores and the risk of incident depression in the SUN Project. BMC Medicine, 13, 197-197.
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