We explain what the latest research can tell us about how different food makes us feel, and why.
It's not uncommon to find yourself smacking your lips and asking out loud, "I feel like eating ... something..." During colder months, we turn to 'comfort foods' to take away the winter blues. But how do we choose what we eat? Do we eat different food when we're happy as opposed to when we're sad? Or does the food we eat determine how we feel? Is it possible to eat ourselves happy? Recent research on the relationship between mood and food has tried to answer these questions and the results have been mixed.
Caffeine – mood enhancer or depressant?
The research: A review of caffeine's effect on mood published earlier this year suggests between 38 and 400mg of caffeine a day could maximise the benefits of the stimulant and minimise its risks.
What it means: Many of us feel our day isn't worth living without coffee or tea to help us through. The caffeine stimulant in these drinks affects a number of 'messengers' in our brain. Caffeine stops us from feeling drowsy, makes our heart beat faster, and helps the body produce more dopamine, a neurotransmitter which makes us feel good. There is, however, a limit to the apparent benefits of caffeine. Too much caffeine can leave you feeling anxious, give you headaches and interrupt sleeping patterns, which doesn't leave you feeling particularly happy.
Take-home message: Up to four cappuccinos or a couple of long blacks each day should keep you happy without the risk of headaches or anxiety. Tea and instant coffee contain much less caffeine than an espresso, so even six to eight cups a day shouldn't keep you awake at night – unless you are especially sensitive to caffeine. If you need a quick fix though, be patient. Caffeine only takes full effect after an hour or so. Meeting your friends at the café gives you the more immediate lift.
Multivitamins and minerals – the secret to happiness?
The research: A link has been shown between depression and deficiencies of folate and B12. Research also shows a lack of vitamin B1 (thiamin), iron and selenium contributes to 'poor mood', irritability and lethargy. B vitamins are vital to the functioning of brain chemicals, particularly dopamine, a mood-enhancer. The body also needs iron and vitamin B12 to produce healthy blood and selenium for hormone regulation.
What it means: A range of vitamins and minerals have been linked to mood in one way or another. But this research has usually focused on participants who have an inadequate diet in some way, or who are depressed or being treated for some form of mental illness.
Take-home message: Following a healthy, balanced eating pattern is a more reliable way of remaining happy than taking particular vitamin or mineral supplements. Bread, breakfast cereals, green vegetables, citrus fruit, red meat, fish, eggs and Brazil nuts are just some of the everyday foods rich with 'feel happy' B vitamins, iron and selenium.
Omega-3 – brain food or happy pills?
The research: Several studies have suggested the omega-3s most commonly found in fish oils have a positive effect on mood. A review of research carried out over the past 10 years agrees there is a plausible explanation for a link, but other studies show there isn't concrete evidence to prove the link.
What it means: Omega-3s are fats crucial to the brain. They make sure signals pass through the brain effectively, enabling us to think and do as we please. Although it makes sense these fats might also make us feel happy, the research so far, which has been focused on treating depression, hasn't proven this to be true.
Take-home message: Omega-3s are good for our brain, if not our mood specifically. Eating foods rich in omega-3s such as oily fish, canned sardines and tuna, walnuts or flaxseed oil will help keep your brain functioning at its best.
Chocolate – fact or folklore?
The research: There are several ways chocolate can influence our mood. Chocolate contains stimulating substances such as caffeine. Chocolate also works on chemicals in the brain which influence how good we feel, and it has an almost perfect combination of components to stimulate our senses – sweetness, texture, taste and smell. This is because of its high fat and sugar content. In 2006, researchers in Sydney tried to establish once and for all whether chocolate does have the much-believed positive effects on our mood. They did confirm the belief that eating chocolate is enjoyable, but made a distinction between chocolate being eaten in response to a craving, and chocolate being eaten for more general emotional reasons.
What it means: When we 'crave' chocolate, it's for the pleasurable eating experience, whereas if we are feeling down, we are more likely to be looking for the 'feel good' factor of the brain chemical dopamine, which is released after eating sweet foods. Either way, science suggests any mood benefits from eating chocolate are short-lived – possibly only the time taken to eat it!
Take-home message: The short-lived nature of the chocolate 'buzz' is not a good reason to over-indulge. As with most foods, if eating some is good, it doesn't necessarily mean eating more is better. Savour the moment while it lasts.
Cravings – how mood affects food choices
The research: A scientist in the US who studied food cravings discovered those who crave food when they are feeling down are most likely to yearn for fatty and sugary foods. Savoury carbohydrates such as pasta and protein-rich foods such as fish or eggs did not rate highly as satisfying cravings as much. The onset of cravings was more likely in the afternoon and evening, and cravings were satisfied with snacks, not meals.
What it means: Eating food containing sugar, such as chocolate or cake, increases the amount of the chemical tryptophan entering the brain. This causes the release of the brain chemical serotonin, which improves mood and, in turn, reduces the desire for more sugar-containing food.
Take-home message: It's not only sugary food which causes the release of serotonin. Eating starchy foods such as bread, pasta or potatoes will help keep you feeling perky. Our body has other craving triggers besides how we feel. The sight and smell of food can also trigger cravings, which is why we can suddenly feel hungry when walking past a bakery or a chocolate shop, without having thought about eating earlier.
Probiotic yoghurt drink – mood booster?
The research: Psychology professors in Wales studied the effect on people's mood after having a probiotic yoghurt drink. Participants who described themselves as having a 'low mood' at the beginning of the study felt happier at the end. Those who were already happy remained happy but didn't feel happier. The scientists also recorded bowel habits and found those who rarely suffered constipation tended to belong to the 'good mood' group.
What it means: Probiotic drinks have been recommended for those with constipation and other bowel complaints because they can help relieve symptoms of several bowel disorders. In addition to the physical symptoms, those who suffer these conditions can be left feeling irritable. Because bowel habits aren't a subject freely talked about, sufferers of bowel disorders can be pretty unhappy.
Take-home message: Probiotic yoghurts or drinks aim to enhance the naturally occurring bacteria in our gut (of which we have millions), and there is some evidence they are effective. Fibre-rich whole grain cereals such as wheat biscuits, wholemeal bread and bran flakes, plus the natural fibre in fruit and vegetables, together with plenty of water and staying active, will also help to keep you regular, healthy and happy.
Sweet and starchy carbohydrates – feel-good food?
The research: The largest amount of research looking at food and mood focuses on the effects of starchy carbohydrates such as bread, pasta and rice, and sweet carbohydrates such as lollies, desserts, cakes and biscuits. The most popular theory is that eating carbohydrates increases the amounts of tryptophan in our body. Tryptophan enters the brain, causing the release of a 'mood-enhancing' chemical. But scientists now believe the amount of mood-enhancer released depends on what else is eaten at the same time. Eating just a small amount of protein at the same time can reduce the amount of tryptophan reaching the brain.
Also well-documented are the changes in blood glucose levels experienced through the day. Every time we eat, our blood glucose level rises, which can make us feel more alert, energetic and possibly happier. But this only happens when our blood glucose level is low, such as in the morning when we haven't eaten since the night before. A sweet taste from chocolate, for example, can also make us feel happier. This is also true of eating a sweet food we know we enjoy – more the effect of an association with past experience than anything physical.
What it means: Sweet and starchy carbohydrates definitely affect brain function and probably mood. Exactly how is still being debated, and there are many foods responsible for mood highs and lows.
Take-home message: Including breakfast cereal, bread, pasta, rice or potatoes as part of each meal will ensure a steady supply of carbohydrate during the day to keep our blood glucose levels stable. Similarly, sweet food is best enjoyed within a meal rather than as snacks.
The effect of food on our mood is subtle, hard to measure and often disappointingly brief. How our mood influences the food we choose to eat is largely individual. If it's instant gratification we're after, socialising with friends or being active can be just as effective. No-one can deny eating is one of the greatest pleasures in life, but exactly what makes us feel good is hard to define. Is it the food, the company, where we are or the time we eat? The truth is probably a mixture of these factors.