Can you tell me which foods promote collagen?
Collagen is classified as part of our body's connective tissue. Connective tissue is found virtually everywhere in the body. Our bones and skin are composed primarily from connective tissue, but it's found everywhere, in virtually all of our organs. It's the job of connective tissue to hold things together, to protect other tissue, and provide our body with support. Our tendons and ligaments are all connective tissue structures.
Collagen is one type of fiber found within connective tissue. Collagen fibers are made from protein, and they are somewhat unusual in having large amounts of two amino acids, called hydroxylysine and hydroxyproline. These two amino acids seem to be important for formation of all types of collagen and are needed to provide the different collagen types with their appropriate amount of strength and flexibility.
Unfortunately, we haven't seen any research studies to support the addition of high lysine or high proline foods as a way of promoting collagen formation. Nonetheless, it would seem logical for consumption of foods high in lysine and proline to be potentially helpful in collagen support. Animal foods are the primary source of both amino acids, and all of the World's Healthiest Foods choices involving animal products would be your best options here. We have seen far more research on the lysine content of food than the proline content of food.
With respect to proline, egg whites appear to be an especially good source of proline from amongst the animal foods. And we've found one important exception to the animal versus plant proline rule - wheat germ. This plant-based component has much more proline than would normally be expected from a plant food.
All of the lean meats that we feature on our website, the low-fat dairy products, and the fish would be especially concentrated sources of lysine. One plant food category would be an exception to the animal versus plant lysine rule - that category is legumes (and particularly peanuts). Legumes are significant sources of lysine, unlike most of their plant food counterparts.
One final note about lysine, proline, and collagen would involve the importance of vitamin C. This vitamin is required to change proline into hydroxyproline (the collagen form) and lysine into hydroxylysine (once again, the collagen form). You can use our website's Essential Nutrients section to find foods highest in vitamin C content.
While you are trying to support your collagen tissue, you should remember that overall protein intake - both quality and quantity - is important. You may need to go beyond the RDA protein level of 46 grams (for adult women) and 56 grams (for adult men) to achieve this goal. You may also need to include a variety of foods that provide protein. Nuts, seeds, and legumes would all be food categories to consider.
Some of the diseases involving collagen damage have been found to improve with the addition of certain foods or food components to the diet. However, the research in this area tends to involve animals versus humans, and the experiments have often used food extracts or nutrient supplements instead of foods themselves. In this category, however, garlic has been a standout food, and two sulfur-containing nutrients - the amino acid taurine and the organic acid lipoid acid - have also shown the ability to support damaged collagen fibers.
Finally, you may want to consider two categories of phytonutrients as particularly important in a collagen-building meal plan. Those phytonutrients are catechins and anthocyanidins. In the research literature, the catechins found in green tea have been shown to help prevent breakdown of collagen, and for this reason we would definitely recommend that you consider green tea as a potential collagen support food. The anthocyanidins found in deep-colored, red-blue berries and fruits (including cherries, blueberries, blackberries, and raspberries) have been shown to work in a somewhat different way. These phytonutrients help the collagen fibers link together in a way that strengthens the connective tissue matrix.