Pig's feet are high in collagen promoting amino acids

Want to have healthy, firm skin? Looking for a way to include foods in your diet to promote optimal skin health? Read this to find out why I recommend consuming bone broth on a regular basis, along with vitamin C-rich fruits and vegetables as often as possible. Just another reason why a properly designed Paleo diet is the best diet for your skin health!

And for more great information about bone broth, check out this great article by Dr. Kaayla Daniel called Why Broth is Beautiful.

As a disclaimer, I wrote this for a nutritional biochemistry class. My professor is pretty anti-supplementation in general, so that’s the tone I took in the paper. Though it’s true eating pure collagen won’t translate into collagen being ‘deposited’ in your skin or anything ridiculous like that, it’s important to supply a wide range of amino acids in the diet, and glycine and proline are particularly important for collagen synthesis. Don’t bother with supplements when you can just make bone broth!

There are many collagen supplements, beverages, and food additives being sold by the nutricosmetics industry as a cure for wrinkles, aging, and skin conditions in general. An example of a product that makes health claims about restoring collagen is “YouTonic”, which advertises a beverage that provides “a natural collagen protein product designed to give you what nature once did—muscle and skin tone, joint flexibility and weight management, along with healthier and rejuvenated bones, arteries, hair and teeth.” However, there is little evidence that manufactured products like this make any significant difference in skin health, and may largely be a waste of money for consumers looking to improve their skin’s appearance.

The rationale for using these types of supplements is that they provide the basic amino acids that are used as the building blocks of collagen, which often have been hydrolyzed for ‘better absorption and utilization’. (2) These beverages also provide vitamins and antioxidants that are intended to boost skin health, such as vitamin C and B vitamins, though many of these vitamins are synthetic and may not be as well utilized in the body as those found naturally in food. Consuming pure collagen is not likely to translate directly into collagen production in the skin, joints, and bone. Collagen is a complex protein structure that must be broken down into individual amino acids in order to be absorbed by the intestinal lumen and passed into the bloodstream. After digestion, the metabolic fate of these amino acids is completely dependent on the needs of the body, the cofactors the body has available to produce its own proteins, and a variety of other factors that dictate the ultimate use of individual amino acids from the diet. The collagen in a supplement, drink, or food product will not remain intact and be used directly as collagen by the skin or any other connective tissue.

In order to understand how collagen supplements are designed to work, it is important to understand the structure and synthesis of collagen in the human body. Collagen is the most abundant protein found in mammals, making up about 25 percent of the total proteins in the human body. (3) Its structure is a triple helix made up of intertwining α-chain polypeptides, and is especially rich in the nonessential amino acids proline and glycine. These two amino acids make up collagen’s characteristic repeating motif Gly-Pro-X, where X can be any amino acid. (3) Collagen is formed when procollagen, formed in fibroblasts, osteoblasts, and chondroblasts, is secreted into the extracellular matrix and is enzymatically modified to form mature collagen monomers that form the cross-linked structural fibers that are found in skin, joints, and bone.

Vitamin C is required during the procollagen production stage, particularly during hydroxylation of lysine and proline to cross-link the α-chain polypeptides. (3) A lack of vitamin C, like in the disease scurvy, leads to the procollagen chains not being hydroxylated sufficiently to form stable triple helices at normal body temperature, and they cannot form normal fibrils. (3) As a consequence, these non-hydroxylated procollagen chains are degraded within the cell, and the health of the skin, joints, tendons, and blood vessels suffer.

Due to the fact that collagen is digested into individual amino acids in the body, and those amino acids can be used for a wide variety of different metabolic processes, I don’t think that collagen supplements are necessary for synthesis and maintenance of skin health, and are likely cost ineffective. The amino acids that make up collagen, proline and glycine, are nonessential, which means the body can product them on its own without dietary input. So theoretically, as long as the diet contains adequate essential amino acids, the body should be able to create all the proline and glycine it needs for adequate collagen production.

That said, I do think there is a role for providing an abundance of the specific amino acids that are used in collagen production as a way to optimize skin health. While there hasn’t been any research to demonstrate that a diet high in proline and glycine promotes collagen production, it seems logical that providing high levels of these amino acids in the diet would facilitate collagen production. (4) And while nonessential amino acids can be manufactured by the body, glycine and proline are considered to be ‘conditional’ amino acids that may actually be essential during times of illness and stress. (5) There are measurable limitations to the rate at which conditional amino acids can be synthesized, and when this limit is attained, the amino acid in question becomes an essential component of the diet. (6) For certain individuals who are less efficient at producing proline or glycine, or have greater demands for collagen production (such as burn victims), consuming these amino acids in the diet would be highly recommended.

A recommendation for a diet to support collagen production, in an effort to slow skin aging, should include dietary sources of proline and glycine, as well as adequate vitamin C. Not surprisingly, cartilage and collagen from animal foods like skin, bones, and cartilage are the best dietary sources of proline and glycine, and can be obtained by the consumption of broths made from animal bones and joints. (7) The gelatin that forms when cooking these animal parts is especially rich in bioavailable proline, glycine, and hydroxyproline, and making bone broth is much less expensive than buying hydrolyzed collagen supplements. Bone broth would also provide a great amount of fluid and electrolytes to help with hydration, which could improve skin moisture and promote an overall healthy appearance.

In addition to providing the conditionally essential amino acid building blocks for collagen production, it would be wise to consume a diet high in vitamin C, which is an essential cofactor involved in the formation of procollagen. Foods high in vitamin C include fruits and vegetables such as papaya, bell peppers, strawberries, broccoli, pineapple, kiwi, sweet potatoes, and citrus fruits. (8) By providing adequate levels of dietary vitamin C, the body will be able to optimize its collagen production using the amino acids provided by the diet. Providing the bioavailable amino acids proline and glycine through bone broths, plus including adequate vitamin C through fruits and vegetables, is likely the best way to maximize one’s innate collagen production without needing to spend extra money on unnecessary supplementation.

References:

1. Youtonics Website. http://www.youtonics.com/
2. LifeSource Vitamins. http://www.lifesource4life.com/collagen.html
3. “Collagen: The Fibrous Proteins of the Matrix.” Ncbi.nlm.nih.gov. 2009. http://www.ncbi.nlm.nih.gov/books/bv.fcgi?rid=mcb.section.6542
4. World’s Healthiest Foods. “Can you tell me which foods promote collagen?” http://www.whfoods.com/genpage.php?tname=fightdz&dbid=6
5. MedlinePlus. “Amino Acids.” http://www.nlm.nih.gov/medlineplus/ency/article/002222.htm
6. Reeds, P.J. “Dispensable and Indispensable Amino Acids for Humans.” Journal of Nutrition. 2000;130:1835S-1840S. http://jn.nutrition.org/content/130/7/1835S.full
7. Daniel, K.T. “Why Broth is Beautiful: Essential Roles for Proline, Glycine and Gelatin.” http://www.westonaprice.org/food-features/why-broth-is-beautiful
8. MedlinePlus. “Vitamin C.” http://www.nlm.nih.gov/medlineplus/ency/article/002404.htm