It was once thought that fats, proteins, carbohydrates, vitamins, and minerals were all the nutrients essential for growth and health; however we are now increasingly aware of another group of nutrients necessary for optimal health – phytonutrients. Phyto is the Greek word for plant, meaning that the word phytonutrient (also known as phytochemical) literally means a ‘nutrient from a plant’. Research is revealing that these compounds, responsible for giving plants their colour, have numerous health benefits.
The role of phytonutrients in plants is to protect the plant from disease, injuries, drought, excessive heat, ultraviolet rays, and poisons or pollutants in the air or soil and it’s becoming apparent that many of these benefits can be applied to human health too. Phytonutrients are being linked with a wide variety of health claims including the prevention and improvement of various cancers, heart disease, memory loss, and osteoporosis as well as skin conditions and the process of skin ageing. There are countless phytonutrients in nature, each of which have varying mechanisms of action beneficial to health.
Flavanoids and carotenoids are two well researched categories of phytonutrients.
Flavonoids have various positive impacts on skin blood vessels and capillaries. Three main components of their activity have been identified: blood vessel protection, platelet aggregation prevention, and decrease of capillary permeability. Blood vessels and capillaries supply nutrients to the skin's cells, as well as supporting cellular membranes - maintaining healthy cell membranes ensures they regenerate quickly, slowing the aging process. Flavanoids help reduce inflammation, as well as increasing levels of the potent antioxidant glutathione. Many phytonutrients provide protection from damaging exposure to UV rays. Research shows that curcumin, a flavanoid found in turmeric, inhibits the expression of Cyclooxygenase-2 (COX-2), which is significantly involved in the acute inflammation that follows UVB exposure. It also inhibits proliferation and induces apoptosis of human melanoma cells.
Flavanoids are found in citrus fruits, berries, ginkgo biloba, red onions, pulses, tea (especially white and green tea), red wine and dark chocolate (with a cocoa content of 70% or greater.)
Carotenoids are split into three classes: carotenes - orange and red pigments which are very fat soluble including lycopene. Xanthophylls - yellow pigments including lutein and zeaxanthin and Astaxanthin, a dark pink pigment found in phytoplankton and algae providing the fish and birds which eat them, such as salmon, prawns, lobster and flamingos, with their intense pink colour. Carotenoids provide many of the beneficial properties of flavanoids and have also been shown to give skin a naturally tanned colour by stimulating the synthesis of melanin. A study lead by Dr Ian Stephen at the University of Nottingham found that peo¬ple who had a significant fruit and veg¬eta¬bles per day have a more golden skin tone, due to the carotenoid intake from these foods. Dr Stephen reported that his team found that “given the choice between skin colour caused by sun¬tan and skin colour caused by carotenoids, peo¬ple pre¬ferred the carotenoid skin colour”. Supplements are available which provide concentrated carotenoids for the specific purpose of promoting melanin production to give the skin a naturally tanned colour.
Certain skincare brands incorporate phytonutrient compounds into their formulations to provide a range of therapeutic actions, for example retinoids are commonly used to increase skin cell turnover and address disorders such as psoriasis, acne and photoageing.
Antioxidant - Most phytochemicals have powerful antioxidant activity protecting against the damaging effects of free radicals. Free radicals are atoms, molecules, or ions with unpaired electrons on their outer shell, causing them to be highly unstable and reactive. Antioxidants provide the missing electron helping to neutralise their damaging effects on cells. Free radicals affect the skin in three main ways. They can alter the fatty layers in the cellular membranes which provide structure to the cell and control which nutrients and other agents can pass in and out. They can negatively alter the DNA within cells which can predispose the skin to premature ageing. Altered DNA creates a blueprint for collagen and elastin fibres that don't function as healthy, normal ones would. Free radicals also lead to cross-linking of collagen fibres. This occurs in the skin's dermis, as a result of collagen and elastin fibres becoming harder, thicker, and starting to bind together. Cross-linked fibers create wrinkles, skin sagging, and cause regular expression lines to become permanently etched in the face. With healthy collagen and elastin fibres such expression lines are much more likely to disappear once you moved your facial muscles in a different way. The enzymes that metabolize collagen are encouraged by free radicals, so it is therefore preferable to consume adequate levels of antioxidants in order to discourage proliferation of these enzymes given the importance of collagen in maintaining skin structure and volume.
Regularly consuming a wide variety of fruit and vegetables is fundamental in increasing phytonutrients intake, however it is unfortunately it is hard to guarantee the levels of nutrients one can consume though diet alone. As with many nutrients, the levels of phytonutrients can decline as a plant ages, it is therefore advisable to consume the freshest possible food. Organic fruit and vegetables have been shown to contain higher levels of phytonutrients, believed to be due to a longer growing time giving the plants more time to develop these compounds. Phytochemicals in fresh plant foods are typically reduced or destroyed altogether by modern processing techniques, including cooking, so eating raw or steamed vegetables is preferable. Interestingly, the reverse is true with lycopene, a phytonutrient present in tomatoes, which becomes more bioavailable after having been heated.
The doses of individual phytonutrients studied and proved effective are often much higher than levels which could be obtained from dietary sources. Resveratrol, the compound linked to the health benefits of red wine are typically present in quantities of less than 2mg per litre. A study showed that resveratrol can block early stages of experimental atherosclerosis, however the dosages used in the study were equivalent to the subject consuming at least five litres of wine per day! Supplements of individual phytonutrients and phytonutrient complexes can ensure guaranteed levels of these beneficial compounds.
What we do know is that phytonutrients work synergistically, meaning when they are consumed together certain compounds enhance each other’s availability and actions. In one study, curcumin co-supplementation with 20 mg of piperine (extracted from black pepper) significantly increased the absorption of curcumin by 2000% within the first hour. This reiterates the importance of having a variety of different fruit, vegetables and spices in the diet.
As research continues and our understanding of the benefits of phytonutrients grows, it is likely that we will see the use of phytonutrients for skin health increasing both in the form of nutritional supplements, as well as topical skin products.