Many people are in pursuit of a clear, youthful, glowing complexion but does what we eat really make a difference? Numerous studies have linked diet not only to ageing skin but also tobskin disorders such as acne, eczema and atopic dermatitis. The body is made up of many interconnected systems and the relationship between the gut and the skin is often called the “gut-skin axis”.
The skin is the largest organ in the body and is part of the Integumentary system. It is our first line of defence again against the external environment as well as being a route of detoxification. The skin is made up of 3 main layers: the epidermis, the dermis and the subcutaneous tissue.
The epidermis is the outermost layer and mainly consists of keratinocytes which are cells that produce a protein called keratin that makes up skin, hair and nails. The epidermis protects our body from pollution, pathogens and UV radiation and helps to retain water , keeping the skin hydrated.
The dermis is the middle layer and helps support and strengthen the skin. It is made up of collagen and elastin and nourishes the epidermis whilst regulating skin temperature.
The bottom layer is the subcutaneous tissue which is mainly comprised of fat and sits in between the skin and muscle. It connects the skin to our internal organs and insulates against changes in temperature.
HOW OUR SKIN AGES
Intrinsic ageing is the natural ageing of all our organs and is determined by our genetic clock. There is a reduction in our subcutaneous tissue causing hollowed cheeks and eye sockets and as bones shrink due to bone loss, the skin begins to sag and lose its firmness.
Extrinsic or photo ageing is caused by exposure to oxygen, UV radiation, chemicals, stress, smoking and pollution along with repetitive facial expressions and of course diet! Extrinsic ageing presents as wrinkles, thinning of the skin, pigmentated spot formation, pale/grayish skin (pallor) and dullness.
The epidermis becomes thinner, the turnover rate decreases and the area where the epidermis and dermis come together begin to flatten reducing the plumpness of the skin.
Collagen and elastin production slows down causing the skin to sag and unable to spring back into place.
Whilst sun exposure has many benefits, too much at the wrong time of day can be detrimental to the skin. UV radiation can cause DNA damage and keratinocytes to release cytokines which can cause inflammation and ageing in the skin. The production of hyaluronic acid which helps keep the skin hydrated and plump is inhibited and tissue can begin to degenerate.
Oxidative stress caused by external factors results in the production of reactive oxygen species (ROS) which can induce DNA damage causing a skin inflammatory response which results in a reduction of antioxidant enzymes and the activation of protein complexes that inhibit collagen production.
HOW DIET CAN HELP
It has long been known that nutritional deficiencies can cause a change in the appearance of the skin. A niacin (vitamin B3) deficiency may result in dermatitis and a zinc deficiency can cause poor wound healing and skin lesions. A Vitamin C deficiency can manifest as skin discolouration, poor wound healing and abnormal hair growth due to Vitamin C being required for collagen synthesis.
Vitamin C and glucose have a similar structure and enter cells using the same pathway therefore eating high glycaemic foods which metabolise into glucose quickly could be preventing you from absorbing vitamin C. Glucose also attaches to proteins and creates Advanced Glycation End Products (AGEs) which are free radicals that damage other proteins around them such as collagen and this can cause collagen cross linking.
Therefore, eating a diet full of high glycaemic foods such as cakes, biscuits, sugary breakfast cereals, potatoes, chips, crisps, white rice and bread and even some fruit can be detrimental to your skin.
Studies have shown that a higher fatty acid intake may reduce premature ageing of the skin. An essential fatty acid (omega 3 and omega 6) deficiency can manifest as increased transepidermal water loss which results in dehydrated skin and dehydration lines can lead to wrinkles. Omega 3 fatty acids can also reduce collagen damage from sun exposure. As we are not able to synthesise essential fatty acids, we must obtain these from foodsuch as oily fish, nuts and seeds.
Protein is needed for the maintenance and repair of tissue cells whilst small peptides, vitamins and minerals are required for the development of dermal and epidermal structures. Food is the easiest way to acquire all of these nutritional factors.
Polyphenols such as green tea and resveratrol which is in grapes, blueberries, cranberries and cocoa are photo protective, antioxidant and increase cell repair. Carotenoids such as B-carotene in carrots and lycopene in tomatoes help to repair collagen and elastin fibers damaged by UV radiation and vitamin E has antioxidant properties and is protective against liver spots.
There are many other nutrients and phytochemicals that are beneficial to the skin but avoiding processed foods, in particular sugar and refined carbohydrates whilst focusing on a whole food approach with adequate protein, healthy fats, fruit, vegetables, nuts and seeds is a good place to start.