Can we eat our way to mental well-being?by Donna Chisholm
Donna Chisholm explores the growing evidence that we can.
No one missed her and the party was still in full swing when she returned so cold, wet and dishevelled that a waiter asked to see her invitation. She was bedridden for three months and unwell for the next 18. A mother of five, she didn’t do the school run for two years. It was her second bout of major depression and it left her so ill, she feared she wouldn’t survive.
So it’s no surprise that when Kelly visits New Zealand 14 years on to promote The Happy Kitchen, her new book about how to use food to manage depression, she doesn’t come over all happy-clappy and suggest we flush our anti-depressants down the lav. “Most studies show the nutritional effects are on mild to medium levels of anxiety and depression, and when you’re having an extreme episode,when you are absolutely suicidal, you can’t imagine a dietary intervention is going to be strong enough.”
She notes, though, the obvious drawbacks about drugs: they don’t work for everyone and are probably best used short- rather than long-term, and when they do work, they take time to kick in.
“There are limits to the medication approach, and nutrition is where the future is. Even if you go down the medical route, which is obviously what I did, the drugs are more effective with a better diet. I never tried it when I was incredibly ill, but if I had a third major depressive episode now – and I hope it doesn’t happen – I would hang on tight to all these nutritional things and hope they made a difference.”
A growing body of international research, including studies at King’s College London, Deakin University in Victoria, Australia, and our own University of Otago, suggests diet could well have a substantial, and rapid, impact on mental health.
In January, researchers at Deakin, headed by its Food & Mood Centre director, Professor Felice Jacka, published the results of the world’s first randomised controlled trial to test whether improving the quality of the diet could treat clinical depression. After 12 weeks, a third of those in the dietary support group had significantly improved mood and symptoms, compared with 8% of those in the group receiving only social support.
A month later, a University of Otago study, led by senior psychology lecturer Tamlin Conner, reported its findings that young adults who increased their fruit and vegetable intake for just two weeks reported an average 25% increase in feelings of vitality and well-being.
The findings follow work by King’s College professor of psychiatry Carmine Pariante, whose team published data in 2014 indicating omega-3 fish oil might help to prevent depression linked to increased inflammation.
A former journalist for the Times, Kelly says she’s taken a similarly evidence-based approach to the book. “Nutrition is a very big area with a lot of confusing information and different dietary advice. As a reporter, I like to properly research things.”
The Happy Kitchen is the result of five years’ collaboration with nutritional therapist Alice Mackintosh, who has worked in a Harley St clinic and has degrees in nutritional therapy and biomedical science. The chapters chart the path Mackintosh took in helping Kelly improve her mental health, from first tackling her fatigue and anaemia, before finding dietary tools to manage low moods, anxiety, mental confusion, hormonal imbalance and sleep disruption.
The book also explains the possible mechanisms by which the diet can trigger poor mental health, including its effect on our gut microbiota, immune system, gene expression and brain function.
Kelly says her GP first mentioned “happy foods” – dark green leafy vegetables, oily fish and dark chocolate – many years ago, but until she consulted Mackintosh, facts on which to base a new dietary regime were hard to find.
“In the UK, our GPs don’t have any nutritional training … maybe just a couple of hours. I felt quite at sea. Even though I had this seed of an idea from my doctor, I didn’t know how to go about it.
“Alice came up with the acronym CRAP – Carbonated drinks, Refined sugars, Additives and Aspartame [artificial sweetener], Processed meat and Processed foods. Within days of actually 100% trying to cut those out, my mood started to improve.”
Like many of us, Kelly would crave a sugar rush when stressed. “I’m absolutely classic in that I had a very emotional attachment to sugary food, going right back to my childhood. If I fell over, Mum would say, ‘Oh don’t worry, have a biscuit and you’ll feel better.’
“Having had a long experience of battling depression and anxiety and not being particularly conscious of the impact of food, [giving that up] was a big challenge for me.”
But when she did, she quickly discovered her mood swings were linked with sugary foods. “I’d get the dip after the sugar rush, feel anxious, then want more sugar and then get the dip again. It was feeding my own anxiety. I’d drink Diet Coke and it made me more jittery.”
The dietary recommendations in Kelly’s book are common sense, the sort of advice that’s now well accepted as enhancing all aspects of health: eat mostly plants, up the intake of oily fish and reduce refined carbs.
“I wasn’t an unhealthy eater,” she writes. “At heart, I was a meat-and-two-veg sort of girl, not unfamiliar with more exotic ingredients like quinoa … I wasn’t averse to the odd avocado, spinach and almond milk smoothie, but I was an unadventurous cook.”
The description makes her life sound misleadingly mundane. Stories in UK papers about her books – the first was her 2014 depression memoir Black Rainbow – make much of her glamorous, seriously moneyed lifestyle and how she seemed to have it all: children, a happy marriage to former Goldman Sachs banker and Oxford old boy Sebastian Grigg (a close mate of former PM David Cameron) and a high-profile job in journalism. But Kelly seems refreshingly free of the sense of self-entitlement wealth can bring. In Black Rainbow, she describes a run-in with her nanny, who has little empathy for her illness, telling her employer, “I don’t believe in depression. Some people have nothing to be depressed about.”
Instead of sacking her on the spot, Kelly says she felt her heart thud and her stomach lurch. “I found myself wondering if she was right.” Certainly her comfortable lifestyle afforded her no protection. “Choice is paralysing for those with depression,” she writes.
“Life was good, but I was definitely an anxious and striving type,” Kelly tells the Listener. “I was 34 [before the first breakdown], and basically I took on too much.”
The disastrous 2003 Christmas party came just two months after she gave birth to twins and in the face of increasing bouts of anxiety. Her efforts to keep her condition secret compounded her exhaustion.
She says most people recovering from depression or battling less severe episodes tend to have peaks and troughs. “I’ll still have periods of quite intense anxiety, and what I’ve been trying to do is learn strategies to make a third depressive episode less likely. It’s like the sleeping dragon, but for now it’s still asleep.”
Stopping it from waking again is largely down to her diet, she says. “My energy levels definitely improved with the first interventions: establishing a routine, balancing my blood sugar, increasing my iron. Then things become a virtue circle.”
She says it’s important not to reduce the variety of the foods we eat, but to increase them. “Modern western man probably eats about 20 different ingredients each week; ancestral men ate 150.”
But like most cause-and-effect scenarios in mental and physical health, one dietary size doesn’t fit all, beyond the broad-brush recommendations already referred to: eat more vegetables, increase dietary fibre (most westerners eat about 10g a day, when we need 50g), reduce saturated fat and reduce sugar.
“It’s very, very complex,” Deakin’s Felice Jacka told the Listener, pointing to a 2015 study of 800 participants, in which Israeli researchers found blood-glucose responses to the same foods were very different, depending on the makeup of an individual’s gut bacteria.
“Based on the microbiome data, they were then able to work out an ideal meal to keep their post-prandial glucose response low. So if you have information on the microbiome, you can start to move towards personalised recommendations.”
Diet impact varies enormously
The impact of diet on mental health is likely to vary enormously between individuals, she says. “When we think about risk factors for depression, the primary one is genetic, but we know diet and other factors alter the way genes are expressed. The other risk factors are around early life trauma, life stress, a whole range of things. For one person, a poor diet may be enough in and of itself to induce depression. For someone else, diet might modify the risk lever up and down.”
However, she says, there’s now plenty of evidence to show that the diet is as important to mental health as it is to physical health. “Physical and mental health should be considered two sides of the same coin.”
Jacka says a top priority for improving the diet is increasing daily fibre intake. “That’s the main issue, because the microbiome can’t do what it’s supposed to do without it.”
Some research papers describe the gut-brain axis as the “missing link” in depression, with gut microorganisms capable of producing and delivering neurotransmitters such as serotonin, which has a key role in regulating mood. The state of the gut microbiota has been associated with schizophrenia, autism, anxiety and major depression.
At birth, babies inherit their microbiota from their mothers, but diet in the first three years of life also plays a critical role in determining the microbiome footprint in adulthood. Having that footprint doesn’t mean it’s impossible to alter, though.
“You can change your microbiome within 24 hours by changing your diet. And there are fantastic studies showing you can improve the health of your gut and reduce the inflammatory markers in the bowel with only two weeks of a changed diet.”
Jacka acknowledges it can be difficult to tease apart cause and effect – does mental ill-health cause a poor diet rather than the other way around? She says most published studies that have investigated whether the illness comes first have ruled it out, and a Deakin paper last year showed a past experience of depression is associated with better diets over time.
Recent American studies have also found the potential protective effects of a healthy diet on depression seem particularly pronounced in people with diabetes, and that dietary counselling is as effective as psychotherapy for reducing the risk of people suffering some depressive symptoms from progressing to full-blown clinical depression.
At the University of Canterbury’s Department of Clinical Psychology, Professor Julia Rucklidge has been researching the effects of a group of dozens of micronutrients on people with ADHD, finding that those who took them improved their well-being and ADHD symptoms more than those taking a placebo.
She’s soon to seek ethical approval for a new study, using the same set of micronutrients – including vitamins A, C, D, E and all the Bs, thiamine, riboflavin, magnesium, calcium, iron, phosphorus, iodine, zinc, selenium, copper, manganese, chromium, molybdenum, potassium and some amino acids – in people with low mood and depression.
The nutrients are based on a formula developed in Canada, where Rucklidge gained her PhD before coming to New Zealand in 2000.
Rucklidge hopes to launch the study through GPs’ offices, recruiting 120 people, about 70-80% of whom will have major depression, and giving half of them the micronutrients and half a placebo.
She’s also examining the impact of nutrients on depression in pregnancy and hopes to analyse gut bacteria in those women, although this information may not be collected in the other trial.
Taking the micronutrients involves a regime of 12 tablets a day, which might seem simpler to some than a diet and lifestyle overhaul. “That’s not the message I want to be giving, though,” says Rucklidge.
“What I’m trying to achieve is to put nutrients on the map. At the moment, the standard treatment for mental illness is medication and/or psychotherapy. We want people to start thinking about nutrition and how relevant it is to mental health.
“There are some people who need the nutrients we give, absolutely, but we also want to start changing society’s view about it because at the moment, many people would think nutrition was irrelevant.”
She worries that people reading this might be tempted to head to the supermarket and clean out the supplement shelves. Don’t do it, she says.
“It’s a tricky one. Most supermarket brands aren’t researched for the treatment of mental illness. People latch on to the nutrients themselves, and although they’re important, it’s also the dose. Supermarket doses are nothing like those we use in research. They’re based on preventing you from getting a nutritional disease like scurvy, not for brain health, to really reverse something that’s pretty complex.”
Rucklidge acknowledges some people with woeful diets can, with natural resilience, have excellent mental health, while those who eat well can become ill.
“Anecdotally, we’ve seen people with amazing diets who come into our research and do really well on the micronutrients,” she says, “which suggests some people need more nutrients than they can get out of their food.”
Although Jacka and Rucklidge stress the complexity of the issue, new research by the University of Otago also illustrates the potential benefits of simple, short-term dietary changes.
Tamlin Conner’s study, published in the open-access journal PLOS One in February, found young adults given fresh fruit and vegetables for two weeks reported better psychological well-being than those who were not. Conner says the young people (aged 18-25) had diets low in fruit and vegetables before the study.
The 171 participants were divided into three groups: a diet-as-usual control, a group given the fruit and vegetables and a group given a voucher to buy their own fruit and vegetables. The control group and the voucher group didn’t report any psychological benefits.
“We think the nutrients in the fruit and vegetables are important for healthy brain function, but I can’t say what those mechanisms are.”
She says she can only speculate about why the group given the vouchers didn’t report any improvement.
The group given the produce (carrots, apples or oranges, and kiwifruit) tended to eat them raw, while those who bought their own cooked them. “One possibility is that the difference might be due to lower control over the type, quality and preparation of the fruit and vegetables.”
She says the 25% average improvement in the intervention group “is pretty significant over two weeks”.
Diet can have an “enormous impact” on mood and it isn’t well recognised, she says.
“I’m not advocating diet as a way of treating mental illness. Diet is only one behaviour in an arsenal of things people need to do to improve well-being, but for certain populations, such as those who have really poor diets, this could have a very big impact. And there’s no evidence it does any harm.”
Kelly and the scientists acknowledge that many of us know what we should be doing to improve our diet, but we simply don’t do it.
Kelly is now a passionate advocate, but she admits the required changes haven’t been easy. “It was incredibly hard. Unbelievably hard. It’s taken a very long while.”
A turning point was changing her mindset about food. “There are a couple of ways of thinking about food that really help. The first is the idea that food is your friend; it’s on your side.
“A lot of the thinking about food is quite negative – don’t do this, don’t have that. Cut this out, it’s bad.
“Those are very judgmental words. Rather than demonising it, think of food as supportive, and you can take decisions six, seven or eight times a day for your health.
“It’s a key psychological shift.”
The good mood guide
Deakin University’s Food & Mood Centre makes these recommendations for changes to the diet that can improve mental health.
- Follow “traditional” dietary patterns, such as the Mediterranean, Norwegian or Japanese diets.
- Increase consumption of fruits, vegetables, legumes (for example, chickpeas, lentils, tofu), wholegrain cereals, nuts and seeds. They should form the bulk of the diet, because they are nutrient-dense, high in fibre and low in saturated and trans-fatty acids.
- Include a high consumption of foods rich in omega-3s, such as oily fish. Higher fish consumption is associated with a reduced risk of depression.
- Limit your intake of processed foods, fast foods, commercial bakery goods and sweets.
- Replace unhealthy foods with wholesome nutritious foods. Healthy and unhealthy dietary patterns are independent predictors of lower and higher depressive symptoms, respectively.
- Zinc supplementation appears to be helpful for depression in conjunction with other treatments.
- Vinegars such as balsamic and apple cider appear to be very beneficial to the gut, as are fermented foods such as sauerkraut, kimchi, kombucha and tempeh.
This article was first published in the May 13, 2017 issue of the New Zealand Listener.
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