Do I need to eat a rainbow?

Dr Sue Kenneally

Whether in my GP surgery or in social media groups I hear this all the time, and it is true that on average a vegan diet is healthier than a standard Western diet. And lest we forget, many people who adopt a vegan lifestyle do so for ethical and environmental reasons and have absolutely no interest in eating a healthy diet! I have nothing but the deepest respect for them, but I’m a health professional so it’s my job – and also something of an obsession – for me to very much have an interest in healthy eating. Plant-based diets have a wide range of health benefits, including reduced risk of heart disease, some cancers, diabetes, obesity and others besides. So if you’re vegan why not make the most of it and get all the health benefits along with the ethical and environmental advantages.

A vegan diet is not the same as a plant-based diet; it is perfectly possible to eat a diet that does not involve animal products in any way and still exist on ‘junk’ foods. Refined sugar, white flour, vegetable oils, salt, energy drinks and most alcoholic beverages are all vegan and known to be associated with many chronic diseases. And while I’m delighted to see an exponentially expanding range of vegan ready meals at supermarkets these days, it’s increasingly easy to buy vegan junk food too. That’s great, but you don’t get the same health benefits if you eat lots of processed food, even if it is vegan. Here at Plant-Based Health Professionals UK we recommend a whole food plant-based diet based on vegetables, fruits, nuts, seeds, wholegrains and legumes, and for good reason; it’s all about micronutrients. Instead of being too concerned with the big components of diet, the macronutrients (that’s carbs, fat, protein and alcohol), think along the lines of eating plenty of micronutrients – vitamins, minerals, antioxidants, anti-inflammatory compounds etc for health. And micronutrients are found almost exclusively in plant foods, we will look in more detail at these later.

First a bit of myth busting:

‘I eat a low carb, high fat diet but I get plenty of micronutrients from green leaves’ – Well, yes you do get a lot of micronutrients from green leaves, but there are lots of other types of micronutrients that are not in green leaves, but are in other plant foods and you need these too.

‘I can get all my vitamins and minerals from a supplement’ – again, yes you can get all of the vitamins and minerals that we currently know about from just taking a pill, but there are a couple of issues with this. Firstly, there are almost certainly countless vitally important micronutrients in our food that we just haven’t identified yet, and if we don’t know about them then they are not in your vitamin pill. Also, it is very common in nutrition science to identify a new (for example) antioxidant, nd a way to make it in a lab and give it to people to eat – only to nd that it has almost none of the benefits seen when people eat the naturally occurring version in food. This is usually because as humans we don’t eat ‘nutrients’, we eat ‘food’, and the antioxidant – or whatever is being studied – isn’t acting in isolation, there are probably a number of other nutrients in the food which are also giving us health benefits.

Let’s look at a few of our most nutritious foods:

FIBRE: not found in animal products and exclusively in plants, fibre is one of our greatest friends. A diet high in fibre is associated with a reduced risk of death from heart disease and cancer[1] and helps us to maintain a healthy weight[2]. Dr Denis Burkitt famously said that ‘populations that eat little fibre build large hospitals while those who eat large amounts of fibre build small hospitals’. Fibre is found in most plant foods, but other plants contain specific nutrients that are worthy of mention:

CRUCIFEROUS VEGETABLES: (broccoli, caulifiower, kale) contain isothiocyanates which inhibit enzymes that promote cancer development, increase cancer-inhibiting antioxidants, slow the cell cycle and encourage cancer cell death[3].

ORANGE FRUITS AND VEGETABLES: (apricots, sweet potatoes, carrots, squashes) contain beta carotene which reduces oxidative stress, enhances the beneficial effects of nitric oxide, improves lipid profiles and reduces the size of atherosclerotic plaques in arteries[4].

ALLIUM VEGETABLES: (onions, leeks, garlic) contain organosulphur compounds which inhibit carcinogenic nitrosamine formation during cooking, inhibit cell proliferation, encourage appropriate apoptosis, have antifungal and antimicrobial activity, are mild COX inhibitors, have antiplatelet effects, reduce oxidative stress and improve lipid profiles[5.6].

BERRIES: (raspberries, blueberries, strawberries, blackberries etc) contain anthocyanins which inhibit LDL oxidation, improve endothelial function, reduce the production of pro-inflammatory cytokines, inhibit cell proliferation and prevent cancer invasion and metastasis[7,8].

GREEN TEA: contains catechins which improve glycaemic control, improve lipid profiles – and contain a lipase inhibitor so can aid in weight loss[9].

These are just some examples; let’s not forget lycopene in tomatoes, and the multiple health benefits of mushrooms, and the list could go on seemingly ad infinitum. Each different plant food group makes its own contribution to overall health, so it is very important to eat foods from all of them where possible.

In summary, the evidence is that a whole food plant-based diet is associated with a reduced risk of many of the diseases that cause the most disability and death here in the UK. To get these benefits you need to eat a wide range of different plant foods as they generally work together to produce great results – and it’s not just about planning for your older age, the chances are you’ll be a healthier weight, have a clearer mind and have a lot more energy to get around to doing all the things that make life worth living right now too. Win win!

REFERENCES

1.  Hajishafiee M, Saneei P, Benisi-Kohansal S, Esmaillzadeh A. Cereal fibre intake and risk of mortality from all causes, CVD, cancer and inflammatory diseases: A systematic review and meta-analysis of prospective cohort studies. Br J Nutr. 2016. doi:10.1017/S0007114516001938
2. BA S, I C, JC S, WPT J. Diet, nutrition and the prevention of excess weight gain and obesity. Public Health Nutr. 2004. doi:10.1079/PHN2003585
3. Clarke JD, Dashwood RH, Ho E. Multi-targeted prevention of cancer by sulforaphane. Cancer Lett. 2008. doi:10.1016/j.canlet. 2008.04.018
4. Ciccone MM, Cortese F, Gesualdo M, et al. Dietary intake of carotenoids and their antioxidant and anti-inflammatory effects in cardiovascular care. Mediators Inflamm. 2013. doi:10.1155/2013/782137
5. Nicastro HL, Ross SA, Milner JA. Garlic and onions: Their cancer prevention properties. Cancer Prev Res. 2015. doi:10.1158/1940-6207.CAPR-14-0172
6. SEKI T, HOSONO T. Prevention of Cardiovascular Diseases by Garlic-Derived Sulfur Compounds. J Nutr Sci Vitaminol (Tokyo). 2015. doi:10.3177/jnsv.61.S83
7. Wang LS, Stoner GD. Anthocyanins and their role in cancer prevention. Cancer Lett. 2008. doi:10.1016/j.canlet.2008.05.020
8. Reis JF, Monteiro VVS, Souza Gomes R, et al. Action mechanism and cardiovascular effect of anthocyanins: A systematic review of animal and human studies. J Transl Med. 2016. doi:10.1186/s12967-016-1076-5
9. Legeay S, Rodier M, Fillon L, Faure S, Clere N. Epigallocatechin gallate: A review of its beneficial properties to prevent metabolic syndrome. Nutrients. 2015. doi:10.3390/nu7075230