Because protein is such an important nutrient, you might think that more might be better for your health. The fact is that protein, like other nutrients, has a healthy intake range. Eating excess amounts can carry health risks, just like a deficiency. The recommended daily allowance for protein is 56 grams per day for adult men and 46 grams for adult women. If your diet exceeds these figures over the long term, you might notice negative side effects in your skin and eyes, due in part to the way your body metabolizes protein.
Proteins differ chemically from fats and carbohydrates. Metabolism of protein requires different enzymes than the other two. Unlike carbs and fats, protein does not store in the body as protein. Rather, a continuous process of protein breakdown and synthesis occurs. The body replaces cells that die. This process requires protein metabolism to produce replacement cells. Protein metabolism requires more water than fats or carbohydrates do. An excessively high intake of protein, therefore, can lead to dehydration, which will directly affect your skin and eyes.
While your body can handle excess protein for a short period, it will alter the water balance in your body. Dehydration occurs when your body has less fluid than it needs for normal functioning. You might experience a dry mouth from lack of moisture. Your skin may become dry and itchy. Your eyes will also feel dry from a lack of tears. If you are highly active, you are at an increased risk for these symptoms to occur, explains the American Council on Exercise. In addition, if you don't drink enough water, your symptoms might worsen, leading to more serious complications.
Your body's inability to produce enough tears can cause eye irritation. You might experience a stinging sensation or burning. You may find it difficult to wear contact lens, especially when trying to remove them. Your tears continually bathe your eyes in fluids. This serves a protective function. Dehydration resulting from a high-protein diet can put you at greater risk of eye infections or inflammation. Likewise, dry skin can begin to crack. If you experience itchiness, scratching might increase your risk for secondary bacterial infections.
Eating a high-protein diet lets you feel sated, and that might help to control your appetite. However, it might also replace other foods and nutrients essential for good skin and eye health. If your diet lacks fruits and vegetables, you could develop deficiencies in nutrients such as vitamin C. This vitamin is vital for the synthesis of collagen, which gives your skin its elasticity. To maintain good health, your diet should include a variety of foods groups, with a healthy balance of 10 to 35 percent of your calories from protein.
- Centers for Disease Control and Prevention: Protein
- "Principles of Anatomy and Physiology"; G. Tortora et al; 2005
- American Council on Exercise: Q: Are There Any Risks Associated with Excess Protein Consumption?
- University of Maryland Medical Center; Dehydration; Linda J. Vorvick; August 8, 2009
- MayoClinic.com; High-Protein Diets: Are They Safe?; Katherine Zeratsky; June 19, 2010