Beat the Blues with your plate: Can a fibre-rich diet fight depression?

A recent meta-analysis of 18 studies, published in the journal Nutritional Neuroscience, found that a high-fibre diet significantly reduces the odds of depression, with five times greater benefits for adolescents than adults

Feeling down? What is on your plate might be playing a bigger role in your mood than you think. Depression is a growing concern in India, and while therapy and medication are essential tools for treatment, emerging research confirms that food profoundly impacts mental well-being.

A recent meta-analysis of 18 studies, published in the journal Nutritional Neuroscience, found that a high-fibre diet significantly reduces the odds of depression, with five times greater benefits for adolescents than adults. A team of researchers led by Faezeh Saghafian from the Department of Community Nutrition, School of Nutritional Sciences and Dietetics at the University of Medical Sciences in Tehran, Iran, conducted a systematic search of electronic databases, up to May 2021.

Data from 18 publications (12 cross-sectional, five cohort and one case–control studies) on dietary fibre consumption in relation to depression or anxiety were included. For depression, 15 studies were conducted on adults and three others on adolescents. The review concluded that high intake of dietary fibre was protectively associated with depression in adults, in a dose–response fashion.

The study showed that the total dietary fibre intake was associated with a 10% lower odds of depression in adults and a 57% lower odds in adolescents. Dose–response meta-analysis revealed an inverse linear association between total dietary fibre intake and odds of depression in adults; such that each 5-g increase in total dietary fibre intake was associated with a 5% reduction in risk of depression.

An inverse significant association was observed between intake of fibre from vegetables and soluble fibre and odds of depression. However, cereal fibre, fibre from fruits and insoluble fibre were marginally associated with a reduction in depression, according to the study.

Depression in India

According to the 2016 National Mental Health Survey one in every 20 people in India suffer from depression. Conducted by the NIMHANS, depression was reported to be higher in women in the 40 to 49 age group and among those residing in metros. Equally high rates were reported from among the elderly with 3.5% of the population affected. The survey, conducted in 12 States, said that common mental disorders that include depression, anxiety and substance use are a huge burden on society affecting nearly 10% of the population.

Hemant Bhargav, Associate Professor of Integrative Medicine at NIMHANS, said with depression on the rise in India, especially in adolescents, it is time to harness the power of the Indian diet, naturally abundant in fibre.

“To boost your mood with your meals, it is essential to embrace the power of fibre while prioritising whole foods. Fill your plate with fresh, seasonal fruits and vegetables, whole grains like brown rice and oats, and protein-packed legumes like lentils that provide a variety of nutrients and fibre to support mental health,” Dr. Bhargav said.

Rainbow on your plate

“The more colourful your meals are, the better. Leafy greens, vibrant gourds, and salads that are boiled and fresh promote mental clarity and balance. Oats, barley, apples, and citrus fruits that are rich in soluble fibre are shown to have a strong connection to lower depression rates,” the doctor explained.

“It is essential to choose freshly cooked meals that are light, easy to digest (you should feel light in the stomach within four hours of eating), and leave you feeling energised, not sluggish. Ignite your digestive fire by adding warming spices like turmeric, cumin, and coriander to your meals. These spices not only enhance flavor but also offer mood-boosting and anti-inflammatory properties. Consider enjoying a comforting kashayam (herbal decoction) with these spices before meals to enhance digestion and absorption,” he said.

Besides, it is very important to create a peaceful eating environment. “Savour each bite with gratitude, and avoid overeating. Taking care of your mind starts with taking care of your body. However, if you are struggling with depression, it is essential to seek professional help. Talk to your doctor or a registered dietitian for personalised advice on dietary changes,” he added.

Nutrient-rich diet

Rebecca Kuriyan Raj, Professor and head of the Division of Nutrition at St John’s Research Institute in Bengaluru, said there have been no studies from India that specifically indicate dietary fibre as a standalone solution for preventing or managing depression. However, there is evidence suggesting that a nutrient-rich diet, of which fibre is an integral part, can play a significant role in the prevention and management of depression.

“Our traditional diets naturally provide a diverse array of nutrients in one meal. A traditional Indian thali, for instance, often includes a mix of whole grains, pulses, vegetables, curd, delivering fibre, probiotics, and micronutrients . These nutrients support physical health and also contribute to mental well-being by improving gut health and reducing inflammation, both of which are linked to mood regulation,” said Prof Raj.

Shift towards ultra processed foods

However, with rapid urbanisation, there has been a significant shift towards ultra processed and convenience foods such as instant noodles, sugary beverages, and packaged meals snacks. These foods are typically high in refined carbohydrates, low in fibre, and often stripped of essential nutrients, she said.

The shift from nutrient-dense traditional Indian meals to calorie-dense, nutrient-poor options may exacerbate mental health issues. Promoting the inclusion of fibre-rich traditional foods in modern diets, such as whole grains (millets, bajra), pulses (dal, chana), and fermented items (curd), could help address these challenges. Alongside, addressing lifestyle factors like physical activity, sleep, and stress management is crucial for a holistic approach to mental health, she added.

The gut-mind connection

“Mental and gastrointestinal (gut) health possess a bidirectional connection. Poor gut health can lead to depression and vice versa,” said Meenakshi Bajaj, nutritionist with the Government Omandurar Multi Super Speciality Hospital in Chennai.

The gut microbiota houses trillions of beneficial and harmful bacteria. An imbalance in the ecosystem, known as dysbiosis, decreases production of neurotransmitters regulating mood. Recent research indicates that the gut functions as a “second brain,” releasing mood-regulating chemicals (neurotransmitters) like serotonin, dopamine, and GABA that play a key role in mental health, she explained.

Pro-inflammatory bacteria such as Eggerthella and Bacteroides, are linked with consumption of ultra processed foods (junk), encouraging growth of harmful bacteria, negatively affecting both gut and mental health.

Dysbiosis also causes a leaky gut. Chronic, low-grade inflammation in the gut is linked to depression. Items such as french fries, fried, processed chicken and meat, promote their growth.

Diets low in fibre deteriorate gut health. Artificial additives such as artificial sweeteners in diet sodas and preservatives in packaged snacks, exacerbate gut dysbiosis.

Poor blood glucose control (dysglycemia) due to diets rich in glycemic index and load and poor in dietary fibre, also create an inflammatory gut environment, increasing the risk of depression.

Ms. Bajaj explained that beneficial gut bacteria ferment dietary fibre to produce Short Chain Fatty Acids, possessing anti-inflammatory properties that support brain health.

Regular consumption of probiotics fermented rice-based beverages (Pazhyadu - leftover cooked rice soaked in water overnight) in the south, and fermented carrot, beet based Kaanji in the north help increasing the diversity of gut bacteria reduce inflammation and promote the production of mood-regulating neurotransmitters.

Published - January 14, 2025 06:32 am IST