Eating fruit and vegetables can help us to maintain energy levels, lose weight and keep skin youthful. It can also promote longevity, specifically by lowering our risk of life-threatening diseases such as cancer and heart disease. But what about the effect on our state of mind?
We don’t tend to hear as much about the psychological benefits of such foods. This is somewhat strange given that four million people in England alone are long-term users of antidepressants.
Or the fact that mental health and associated behavioural problems are the main drivers of worldwide disability, causing over 40 million years of disability in 20 to 29-year-olds.
In this blog, we want to look at why fruit and vegetables are so beneficial for mental health, with reference to the latest literature on the topic.
Fruit and Vegetables for Stress and Depression
There is nothing new in the suggestion that certain foods can influence mental health. To take one example, in 2017 we reported on a study from Australia which showed that for every extra vegetable you add to your plate, your stress level is reduced by 5%.
This was not a small study: on the contrary, it took into account data from 60,000 Aussies aged 45 and over. To break it down further, men who consumed between three and four daily servings of vegetables had a 12% lower risk of stress than those who only ate one serving or less. Women, meanwhile, exhibited an 18% reduced risk.
A separate study by the University of Otago in New Zealand, meanwhile, established that people who ate produce in an uncooked state exhibited higher levels of psychological health than those who cooked.
This latter survey involved a much smaller group of 422 adults between the ages of 18-25, and found that “fruit and vegetable intake (FVI) predicted reduced depressive symptoms and higher positive mood, life satisfaction and socio-emotional flourishing.”
Although processed (for example, canned) and/or cooked fruit and vegetables still had a net positive effect, they “only predicted higher positive mood.”
One of the great things about this study is that it considered and controlled for a range of additional factors known to influence mental health: everything from subjects’ diet and level of physical activity to their employment/financial status and body mass index.
Diet and Mental Health: The 2019 Study
The most recent study on this topic, at the time of writing, was conducted by the Universities of Leeds and York and published in the journal Social Science and Medicine.
Researchers followed individuals over an extended period of time and, controlling for a broad range of factors including income, education and employment status, age, marital status, lifestyle and general health, sought to clarify the effect of diet on mental wellbeing. The results were frankly incredible.
Entitled “Lettuce be happy: A longitudinal UK study on the relationship between fruit and vegetable consumption and well-being”, the 2019 study looked at three ‘waves’ of data collected from over 45,000 Brits between 2010 and 2017.
It found that subjects responded to both frequency and quantity of fruit and vegetables in a ‘dose-dependent fashion’.
Here is one especially insightful passage of the report: “A five-portion increase in the number of fruits and vegetables consumed (on a day with positive consumption)…would be approximately equivalent in magnitude to the estimated wellbeing loss from widowhood (-0.68), and approximately one third of the estimated impact from unemployment, which is known to have one of the largest effects on subjective wellbeing.”
Increasing the frequency of your vegetable consumption from never to 4-6 days per week was also said to “generate approximately the same estimated increase in life satisfaction as being married, whereas moving in the opposite direction (reducing consumption from 4 to 6 days per week to never) generates approximately the same estimated loss in life satisfaction as being widowed.”
It may be difficult to believe that suddenly eating more vegetables could make you as happy as marriage – and yes, some people will quip that it says more about marriage than anything else! – but amazingly, that is what the study showed.
Eating just one extra portion of fruits and vegetables each day, meanwhile, could have the same effect on mental wellbeing as eight extra days of walking a month. The links between exercise and mental health are of course well known.
One may wonder if the same effects can be found in other foods. But the researchers observed “no significant relationship” between the consumption of bread and milk and self-reported mental wellbeing. In common with previous studies, a statistically significant (negative) relationship between smoking status and mental health was also noted.
Reflecting on the substantive positive effects of eating more fruit and vegetables, Dr Neel Ocean at the University of Leeds said that “while further work is needed to demonstrate cause and effect, the results are clear: people who eat more fruit and vegetables report a higher level of mental well-being and life satisfaction than those who eat less.”
The Best Fruit and Vegetables for Mental Wellbeing
The aforementioned University of Otago study was useful for establishing particularly beneficial raw foods for depression and life satisfaction. If you’re the owner of a good-quality juicer, perhaps you should start incorporating more of them in your daily green drink.
The top 10 raw foods for mental health were dark leafy greens like spinach, carrots, cucumber and lettuce, citrus fruits, kiwifruit, grapefruit, bananas, apples and fresh berries.
Other raw vegetables which correlated with elevated mood included celery, red onion, mushroom, cabbage and tomato.
Of course, eating these foods cooked is also likely to have a positive effect on mental wellbeing, particularly if they are not harshly processed. You should make an effort to choose organic due to the greater micronutrient profile.
In addition to the aforementioned, antioxidant-rich ‘super’ foods such as blackberries, blueberries, grapes, raspberries and goji berries are also believed to be highly beneficial as far as mental health is concerned.
Micronutrients for Mental Health and Mood
While it is instructive to consider the types of food which can affect our psychological wellbeing, it’s also important to pay attention to the micronutrients which are abundant in those foods and which, to a large extent, are responsible for the beneficial effect.
This partly explains why raw foods had a more profound effect on markers of mental health than processed varieties, since raw foods contain greater levels of micronutrients. Such micronutrients are also more easily absorbed than in those foods which have been extensively processed.
So which nutrients are we talking about exactly? In a 2017 study entitled ‘Nutritional Psychiatry: The Present State of the Evidence’, the ones which showed the most promise for improving mood and relieving anxiety and depression were folate, zinc, omega-3 (particularly EPA), magnesium, vitamin D3 and vitamin B. Other nutraceuticals like S-adenosylmethionine, N-acetyl cysteine and probiotics were also discussed.
According to Professor Julia Rucklidge, PhD, an award-winning clinical psychologist who has been studying the impact of micronutrients on mental health for the last decade, there has been “over 30 double blind randomised controlled trials using a variety of combinations of nutrients and doses across a variety of mental health conditions showing that we can induce a substantial and clinically meaningful change in symptoms just by using nutrients.”
Repeat that last part: just by using nutrients. For those averse to pharmaceutical interventions, this really is the ultimate goal. In fact, it should be the ultimate goal for all of us, for who honestly would prefer to pop pills than eat healthily?
Professor Rucklidge, a professor at the University of Canterbury, is in the process of conducting a Randomised Controlled Trial (RCT) to assess the efficacy of a specific micronutrient formulation for treating depression and anxiety. The supplement contains 40 ingredients, many of which are present in fruit and vegetables; they include high concentrations of B vitamins, vitamins C and D, and minerals such as selenium, zinc, iodine and iron.
It is not the first study to be overseen by Professor Rucklidge: she previously achieved great results from micronutrient intervention in 2010 and 2011, following two earthquakes in Christchurch. The conclusion of the former left no doubt about the micronutrient formula’s efficacy: “The 16 participants on the nutritional supplement were more resilient to the effects of the earthquake than the 17 individuals not taking the supplement. This effect was particularly marked for Depression scores.”
Perhaps most notably of all, the mental health benefits in terms of anxiety, depression and post-traumatic stress, were sustained at a one-year follow-up.
How Many Portions Per Day for Mental Health?
We are starting to learn more about the influence of people’s diet on their psychological health, but to understand the optimal intake of fruit and vegetables we must consider factors such as: raw or cooked/processed; organic or otherwise; and the absorption capacity of the individual in question.
According to a 2012 study of 80,000 randomly selected British individuals, “well-being peaks at approximately 7 portions per day”. Well-being is of course a broad term, but in this context, seven ‘measures’ were considered: life satisfaction, WEMWBS mental well-being, GHQ mental disorders, self-reported health, happiness, nervousness, and feeling low.
Independent of psychological parameters, a 2017 study suggested we should aim for 10 portions of vegetables and fruit per day to promote longevity, with the majority of that number being vegetables.
For most of us, aiming for somewhere between 7 and 10 portions a day is no bad thing.
Can Dietary Supplements Help?
Daunted by the prospect of eating 7-10 portions of vegetables and fruit per day? A food supplement can offer dense nutritional support. Take Green Vibrance as one example. This comprehensive formula is composed of vegetables, fruit, algae and cereal grasses, and contains high levels of nutrients known to aid mental wellbeing.
At a glance, Green Vibrance supplies over 100% of your Recommended Daily Amount of vitamins A and D, as well as over 50% of your daily vitamins C and K. It also contains appreciable concentrations of iodine, chromium, vitamins E and B12, numerous plant-based antioxidants and 25 billion live probiotics.
As for the food content, it contains many of the beneficial foods mentioned in the University of Otago study, including spinach and other leafy greens, carrots, apples, berries and tomato.
Nutravite Multivite is another supplement you might consider. A one-a-day sublingual multivitamin, these micro tablets provide 100% of your RDA for twelve separate nutrients including vitamins C, D, B7 and B12.
Due to the effective concentrations of nutrients, either of these two options will reduce your need to shoot for 7-10 servings of fruit and vegetables.
In an increasingly over-medicated world, the simple benefits of eating vegetables and fruits should never be taken for granted. On the contrary, we should be shouting the benefits from the rooftops.
While there is much we still have to learn to establish cause and effect, as well as the specifics of the possible mechanisms at work, it’s clear that nutrition plays a major role in moderating our mental health.
And when you factor in the considerable physical upsides, it’s something of a no-brainer.
If you’re interested in learning more about so-called nutritional mental health, this conversation between the aforementioned Professor Rucklidge and Seth J. Gillihan, PhD, is well worth a listen.
According to a 2012 study of 80,000 randomly selected British individuals, well-being peaks at approximately 7 portions of fruit and vegetables per day.