THE RAW VEG MYTH
Common consensus is it’s the sure-fire way to get that wellness glow, but does eating veg raw actually leave you more nourished? WH adds heat to the debate
Should you really eat veg raw?
Some things are better enjoyed in their natural state (cutting those jeans into shorts didn’t work, did it?). And we’ve been led to believe that veg, too, is one of these things. Fresh spinach in your green juice? Yep. Uncooked courgette in your zoats? Sure. And with eateries all over the UK serving produce that’s not cooked, going ‘raw’ has never been easier. But is there really any benefit to eating your vegetables sans heat? In an effort to ingest as many feel-good vitamins and minerals as possible by going raw, you could be missing a trick, say experts. Suffering spinach in your smoothie for all those years may have been pointless. ‘Eating vegetables raw has a cooling effect, which slows digestion and triggers your body to use more energy to pass food through,’ says Melanie Waxman, nutrition and health counsellor at SHA Wellness Clinic. ‘It forces the body into survival mode, which can weaken your gut over time, leading to food intolerances. Your metabolism slows too, which ups the likelihood of weight gain.’ What many raw-veg devotees may not realise is that the cooking process actually works with your body. ‘Raw veg contains fibrous components that are actually indigestible,’ explains nutritionist Lily Soutter. ‘Adding heat helps break down some of the fibres and plant cell walls, which ultimately allows for easier digestion and absorption of nutrients.’ In fact, the cooking process itself releases more fuel. Harvard researchers found that cooked sweet potato provides more calories than in its raw state because it’s less resistant to being digested. More calories? That’s bad, right? No, actually. It just means you need smaller portions of cooked veg to feel satisfied and get the same amount of energy as you would from raw. The researchers suggest that’s why, over the centuries, we’ve developed to instinctively prefer hot grub.
Increased digestibility from cooking also renders some vegetables more nutritious. ‘Often, nutrients are bound to the cell walls,’ says Waxman. ‘Heat breaks down these structures, so those nutrients are more easily absorbed. Fat-soluble vitamins in particular, such as A,D, E and K, are more bio-available in this way.’ What’s more, in some veg, such as spinach, nutritional benefits aren’t released at all unless it’s cooked. ‘Raw spinach contains oxalic acid, which prevents the body from absorbing the vegetable’s rich iron content. However, heat breaks down this oxalic acid, making the iron available to the body,’ explains Waxman. The nutritional benefits can be much greater in some cooked veg and this can have an effect on long-term health. ‘Adding heat to tomatoes boosts the antioxidants lycopene, beta-carotene and lutein, raising the total antioxidant capacity by 60%,’ says Soutter. Indeed, a study in The British Journal of Nutrition found that those who followed a strict raw-food diet were deficient in lycopene, which is crucial for lowering risk of cancer and heart attacks. Cruciferous veg such as cauliflower, Brussels sprouts, asparagus, kale and cabbage also become healthier with heat. ‘When eaten raw, they can suppress the thyroid gland’s production of metabolism-regulating hormones,’ explains Waxman. So what? Well, without sufficient thyroid hormones, you may find yourself gaining weight due to a slowing metabolic rate, plus you’ll feel tired and constipated. Cooking cruciferous veg
using any method helps those with irritable bowel syndrome too. ‘It breaks down the compound raffinose, which can cause bloating and gas,’ says Soutter.
But don’t chuck out your salad spinner just yet – those who swear by raw veg still have a case. There’s some evidence that suggests eating raw lets you ingest more nutrients, because heat can deplete or destroy them. ‘Cooked veg is lower in water-soluble vitamins, which have unstable structures, such as B vitamins, vitamin C, calcium and magnesium,’ says Soutter. ‘Boiling can actually lead to an overall vitamin loss of as much as 60%.’ The longer you cook veg, the more nutrients will be lost, she adds. A study in The Journal of Agriculture and Food Chemistry found that tomatoes cooked for two minutes contained 10% less vitamin C than raw, and as much as 29% less if heated for 30 minutes. ‘It causes the molecular structure of the vegetable to completely change,’ says Tanya Maher, wellness coach and founder of Tanya’s Cafe, a raw-food restaurant and delivery business in London. There are some, like Maher, who believe that raw veg is more, not less, digestible for this reason. ‘When temperatures go above 47ºc, you lose the enzymes in the vegetables that help to break down food,’ she says. And these enzymes aren’t just needed for helping out your gut. For example, myrosinase breaks down glucosinates in broccoli into a compound called sulforaphane, which can kill cancerous cells and fight ulcer-causing bacteria*. But when you add heat, the crucial compound is destroyed. Similarly, raw carrots contain cancer-reducing and cardiovascular disease-fighting polyphenols, while raw cruciferous vegetables have higher amounts of vitamin C*.
From the point of view of maintaining a healthy weight, again raw might be the better option. ‘Some vegetables, particularly carrots, beetroot and sweet potato, naturally contain a lot of starch because they don’t get much exposure to sunlight,’ says Maher. ‘When they’re cooked, the starch is broken down and turned into sugar. Where possible, eat them raw by grating or spiralising them. With the exception of those with a compromised digestive system – due to a leaky gut or irritable bowel syndrome – the average person will benefit from raw, as opposed to cooked, vegetables.’ And Soutter stresses that raw veg and ‘indigestible’ fibres aren’t bad for your digestion, and can even help keep it in good condition. ‘Your body can process it,’ she says. ‘Chewing alters the structure of dietary fibres, which are then fermented and broken down by gut bacteria. During this process, butyrate is produced as a byproduct, essential for keeping the gut wall healthy, and “indigestible” fibre can also help healthy gut bacteria to grow.’
For those who still struggle to eat raw, Maher suggests fermenting – allowing natural bacteria to feed on the sugar and starch in food over several weeks. ‘It introduces beneficial bacteria to your digestive system, which helps break down the fibres so your stomach has very little work to do,’ she says. Waxman agrees: ‘Fermented foods increase the number of digestive enzymes in your gut, helping you absorb more nutrients. Some, such as sauerkraut, have particularly high levels of vitamin C, too.’ So, raw or cooked? It’s not clear cut. ‘It really depends on the vegetable,’ explains Soutter. ‘There are pros and cons either way.’ But do we have our priorities all wrong? ‘More important than whether your veg is cooked or raw, is that you eat enough – not to mention a variety as wide as possible,’ says Maher. Challenge accepted.
‘EATING RAW VEG ACTUALLY FORCES YOUR BODY INTO SURVIVAL MODE’