Our body breaks down carbohydrates in our foods into glucose, a type of sugar. Glucose molecules enter our bloodstream from our food, and we use them to energize our cells. The infrastructure of our skin requires glucose in addition to protein. Appropriate amounts of carbohydrate containing foods can be beneficial, but eating too much sugar in our diet can impede normal skin functions and contribute to various skin conditions.
Glycemic Index and Glycemic Load
The glycemic index is a measurement system that estimates how fast a specific food will cause the blood sugar to rise after it is eaten. The glycemic load measures the total effect on blood sugar and insulin for a particular food item. Although a food such as watermelon has a high glycemic index value, its glycemic load is much lower than spaghetti, which has a lower glycemic index, but much more carbohydrates and calories. The glycemic load value determines the overall impact that a meal will have on our insulin response. When we eat high glycemic index and glycemic load food, a large and fast increase in sugar-induced insulin release occurs. Studies have found that high blood sugar and insulin can impede important skin functions, leading to dysregulation such as excess facial oil production and risk for worsening acne. Another detrimental effect that a high glycemic load meal may have on the skin, is to decrease skin elasticity and collagen, accelerating the onset of wrinkles and skin sag. A more in-depth explanation of glycemic index and glycemic load, along with examples, can be found here.
Glycation is a normal process that occurs throughout the body and within the skin. In this process, glucose causes permanent bonds (aka covalent cross-linking) that form between collagen fibers in the skin. Glycation happens when sugars in our blood buddy up with a protein, forming what we call advanced glycosylation end products (AGEs). The problem with glycation is that it renders these collagen fibers impossible to be repaired. Over time, the skin loses elasticity and strength and becomes more prone to wrinkles and sagging. When there is a high level of sugar in the blood, such as in diabetes, the process of glycation becomes accelerated within the skin. Since the damaging effects of glycation are irreparable, the key is to prevent it from occurring by reducing our intake of sugar and foods that are high in refined carbohydrates.
High sugar and insulin in the blood may contribute to the pathogenesis of many diseases, including obesity, diabetes mellitus, acne vulgaris, and hidradenitis suppurativa. Research is still being conducted to understand how diet and sugar intake affect these skin conditions. Dietary advice should encourage a diet rich in vegetables, fruits, and whole grains, and low in sugars and refined carbohydrates.