By Christie Newman, elenzia Nutritionist
If you want to get a head start at being your best you, look at the colour of your diet, and here’s why- When it comes to sufficiently nourishing your body, most nutritionists will advise you to follow the Mediterranean diet. And quite rightly so! Primarily, it is a more balanced way of receiving all the macro and micronutrients, essential fatty acids and fibre we need to function healthily. Another key reason is it is filled with colourful plant-based foods, such as fruits and vegetables that provide us with important polyphenols. Polyphenols are the compounds that give fruits and vegetables their amazing colours and their diverse molecular shapes are what make those colours differ. They are also found in nuts, seeds, coffee, tea, chocolate, red wine and many more natural plant-based foods. Those last two may have caught your attention, so before you get too excited, we remind you ‘everything in moderation’. These wonderful compounds that make some of our favourite foods and even wine good for us, are proven to be associated with reducing mortality by up to 30% (1). From reducing the risk of type 2 diabetes and coronary heart disease to slowing the signs of aging, their ability to protect us from within is diverse. At a minimum we should all be consuming ‘5 a day’. However, if you look deeper into the research that this recommendation is based on, it is more like a minimum of 10 a day and it is important to focus on not just the amount but the variety too (2). Here’s why: We know polyphenols better as ‘anti-oxidants’ which is why they are often associated with anti-ageing, however more recent research concludes just how vital these antioxidant rich compounds are, so much so we should be calling them ‘polyssentials’. Polyphenols go further than just neutralising harmful free radicals, meaning they reduce oxidative stress slowing the signs of ageing, they also influence a variety of cellular signalling pathways within the body, meaning they can boost the proliferation of healthy cell function which in turn positively impacts different bodily functions. This is where they differ and why eating them in variety is so important. Scientists have identified thousands of polyphenol types and categorise them into 4 main groups (3): - Flavonoids. These account for around 60% of all polyphenols. Examples include quercetin, kaempferol, catechins, and anthocyanins, which are found in foods like apples, onions, dark chocolate, and red cabbage. - Phenolic acids. This group accounts for around 30% of all polyphenols. Examples include stilbenes and lignans, which are mostly found in fruits, vegetables, whole grains, and seeds. - Polyphenolic amides. This category includes capsaicinoids in chili peppers and avenanthramides in oats. - Other polyphenols. This group includes resveratrol in red wine, ellagic acid in berries, curcumin in turmeric, and lignans in flax seeds, sesame seeds, and whole grains. These different groups hold different protective properties. Firstly, the amount and type of polyphenols in foods depend on the food, including its origin, ripeness, and how it was farmed, transported, stored, and prepared (4). Secondly, their variety means they differ in molecular sizes, shapes and weights. This results in some being more suited for specific bodily functions than others. For example, dense polyphenols found in grapeseed are particularly efficient in aiding the cellular functions that support skin (5). Whereas the lighter more delicate polyphenols found in red grapes and blueberries are better absorbed in harder to reach areas such as the brain (6). To simplify, research finds the type of polyphenols in grapeseed - anthocyanins - specifically react UVA-induced oxidative stress within the skin. This reduces the unwanted oxidation of lipids and proteins, the healthy cells in our skin, therefore reducing what we may all know as sun induced skin aging and scientists refer to as photoaging. Whereas the resveratrol found in red grapes and therefore red wine, is a particularly versatile polyphenol. One of the many cellular functions it supports is the memory function due its ability to boost the proliferation of a particular protein in a dense hard to reach area of the brain known as the hippocampus. By boosting this protein, known as neuro growth factor, it increases the life span of neuron cells in the brain needed for better memory. These are a few examples of the many cellular reaction’s polyphenols can positively impact. What this doesn’t mean is by eating as many proanthocyanins as possible you will never have to wear sunscreen again, or by eating nothing but blueberries you can say goodbye to calendar reminders! However, it does give you an indication of why eating a diet that is diverse in polyphenols helps your body holistically support the millions of cellular functions that are continuously occurring at every level within. Thirdly, consuming them through a healthy balanced diet ensures you consume them in their various forms which provides you with the other varied nutrients the body needs to function healthily. Such as the fibre in fruit skins, the essential fatty acids in nuts and seeds and the diverse vitamins and minerals across all food types. In summary, we are becoming increasingly aware of how polyphenols go further than just reducing oxidative stress and have become more conscious of their effects on overall health. Knowing more about polyphenols and their positive influences on healthy bodily functions gives even more reason to follow a healthy balanced diet, like the Mediterranean diet for example. Furthermore, it is clear to scientists and health specialists that the consumption of these compounds come in hundreds of sub-classes that vary in weight and size. So, we have become more aware that some are more suited for specific bodily functions than others. Therefore, when it comes to being the best version of ourselves, our diet is a good place to begin. We already know we need to consume a variety of plant-based foods to ensure we nourish ourselves with a balance of macro and micronutrients - now we know this goes for polyphenols too.
References: 1. Zamora-Ros, R., Rabassa, M. and Cherubini, A. (2013). High Concentrations of a Urinary Biomarker of Polyphenol Intake Are Associated with Decreased Mortality in Older Adults. The Journal of Nutrition, 143(9), pp.1445-1450. 2. Aune, D., Giovannucci, E., Boffetta, P., Fadnes, L., Keum, N., Norat, T., Greenwood, D., Riboli, E., Vatten, L. and Tonstad, S. (2017). Fruit and vegetable intake and the risk of cardiovascular disease, total cancer and all-cause mortality—a systematic review and dose-response meta-analysis of prospective studies. International Journal of Epidemiology, 46(3), pp.1029-1056. 3. Zhou, Y., Zheng, J. and Li, Y. (2016). Natural Polyphenols for Prevention and Treatment of Cancer. Nutrients, [online] 8(8), p.515. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4997428/ [Accessed 19 Aug. 2019]. 4. Tsao, R. (2010). Chemistry and Biochemistry of Dietary Polyphenols. Nutrients, [online] 2(12), pp.1231-1246. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3257627/#B3-nutrients-02-01231 [Accessed 19 Aug. 2019]. 5. Dumoulin, M., Gaudout, D. and Lemaire, B. (2016). Clinical effects of an oral supplement rich in antioxidants on skin radiance in women. Clinical, Cosmetic and Investigational Dermatology, [online] Volume 9, pp.315-324. Available at: https://www.ncbi.nlm.nih.gov/pubmed/27799805 [Accessed 20 Aug. 2019]. 6. Bensalem, J., Dudonné, S., Etchamendy, N., Pellay, H., Amadieu, C. and Gaudout, D. (2018). Polyphenols From Grape and Blueberry Improve Episodic Memory in Healthy Elderly with Lower Level of Memory Performance: A Bicentric Double-Blind, Randomized, Placebo-Controlled Clinical Study. The Journals of Gerontology: Series A, 74(7), pp.996-1007