Benefits of Hydroxyproline for Vegans

Benefits of Hydroxyproline for Vegans

Hydroxyproline (HP), along with glycine and proline, make up 57% of the total amino acids found in collagen, and collagen itself makes up one-third of all the proteins in humans. Collagen is the most abundant protein in the human body and contributes to ensuring the strength and structure of our connective tissues, which includes the bones, blood vessels, cartilage, and skin[1]. HP was discovered in 1902 and was quickly identified as a product from gelatine. Soon after this discovery, HP was found to be an essential component of collagen. Fast forward to the groovy 1960s and it was found that HP is derived from the post-translational hydroxylation of proline (an amino acid found in animal proteins[2]). If you are not consuming collagen as part of your daily diet, I would suggest you make HP a part of your supplement regime otherwise you may be missing this important amino acid precursor. But what if you are a vegan, vegetarian, or pescatarian and not consuming collagen? How do you get this amazing amino acid? Why should we worry about consuming HP?

Health benefits of Hydroxyproline

The good news is that if conditions are right, you can make your own HP out of proline, with a little help from a bunch of other nutrients. What you essentially need to do is ‘hydroxylate’ proline. So, assuming you are getting enough proline in your diet, the hydroxylation of proline is carried out by the enzyme prolyl-hydroxylase. This enzyme requires oxygen, iron, and ascorbate (i.e., Vitamin C) as essential cofactors for the successful activation of prolyl-hydroxylase.

Did you know that without adequate amounts of HP and Vitamin C our bodies lack the ability to successfully heal our wounds? Vitamin C is known to be essential for wound healing and without HP, we can also have extremely poor wound healing and can go on to develop Scurvy (yes, the disease the 18th-century sailors used to develop). Results from studies show that animals will develop Scurvy if the animal's HP synthesis is compromised[3].

Why Hydroxyproline may be deficient in Vegans

It seems from the previous paragraph that we can all make our own HP prom proline and thus it seems pointless to supplement something our bodies can already make. Unfortunately, there are some problems with the before mentioned biochemistry that we need to iron out, and I do mean ‘iron’ out (pun intended).

Vegans don't consume animal products, including meats, collagen, dairy, eggs, fish, or chicken. Whilst not eating these foods can be overcome, studies show that vegans can have certain deficiencies. Studies done with vegan participants have often shown that they frequently suffer iron deficiencies because they don’t consume animal (heme) iron[4]. Without enough iron, vegans can't make the HP from proline, which means they can't effectively generate collagen. Collagen deficiencies often initially show in the skin and studies have found that vegan diets may be detrimental to skin health, due to a collagen deficiency[5].

Why Hydroxyproline Supplementation may be Necessary for Vegans

One way to overcome HP deficiency is to make sure your body is making enough of it. Firstly you need to ensure you consume the number one building block of HP, which as the name suggests is the amino acid, proline. However; as the biochemistry suggests, making HP is a pain in the butt. It requires you to be proline, iron, and Vitamin C replete. Unfortunately, if you are a vegan, eating animal-based collagen is out. So, what does this mean? You are doomed to get scurvy? Not so fast. There is a Plan B.

Supplementing with the amino acid Hydroxyproline is an option. However, we advise that you be careful where you source your HP from. Most suppliers that make HP make it out of animal feathers and other waste materials from animals. While this sounds gross, the result is pure HP, but not a vegan source of HP. When seeking HP as an amino acid, you should ensure that the source is a vegan starting material, you should be able to do this by checking a companies testing results. Going without HP is not a good option as HP is required to stabilise collagen [6] so you need it for a healthy body and to generate strong connective tissue.

A Female Vegan

While all vegans may be lower in iron than their meat-eating counterparts as meat is the best source of absorbable iron, women in particular are at a higher risk of developing iron deficiencies than men. Women of childbearing age require more iron than men and in fact, 20-25% of the world's population (mainly women and children) are iron deficient[7]. The reason for this is that women bleed monthly, losing iron (along with collagen) and potentially compromising their collagen production. A lower collagen production can have an impact on the healthy appearance of skin. Additionally, studies suggest that low collagen status can cause women to have increased cellulite. Supplementation with specific types of collagens that target the skin can reduce the appearance of cellulite by strengthening the skin structure over these troublesome areas[8].

The Take-Home Message

Love your collagen. It is literally holding you together (I mean physically). The best way to get collagen is to eat it, but if you are a vegan, you have to make your collagen. All you need is a diet rich in proline, iron, and vitamin C. The problem arises when you are deficient in one or more of these nutrients. It is very common for women, especially vegan women, to have low iron and without iron, you can't make Hydroxyproline, which means your collagen can decrease over time. The best way around this is to simply supplement with Hydroxyproline from a vegan source, so you can hold yourself together and enjoy healthy skin, joints, and connective tissue.



References

1. Li P, Wu G. Roles of dietary glycine, proline, and hydroxyproline in collagen synthesis and animal growth. Amino Acids. 2018 Jan;50(1):29-38. doi: 10.1007/s00726-017-2490-6. Epub 2017 Sep 20. PMID: 28929384.
2. Phang JM, Liu W, Zabirnyk O (2010) Proline metabolism and microenvironmental stress. Annu Rev Nutr 30:441–463.
3. Chojkier M, Spanheimer R, Peterkofsky B. Specifically decreased collagen biosynthesis in scurvy dissociated from an effect on proline hydroxylation and correlated with bodyweight loss. In vitro studies in guinea pig calvarial bones. J Clin Invest. 1983 Sep;72(3):826-35. doi: 10.1172/JCI111053. PMID: 6309911; PMCID: PMC1129247.
4. Haider LM, Schwingshackl L, Hoffmann G, Ekmekcioglu C. The effect of vegetarian diets on iron status in adults: A systematic review and meta-analysis. Crit Rev Food Sci Nutr. 2018 May 24;58(8):1359-1374. doi: 10.1080/10408398.2016.1259210. Epub 2017 Jul 5. PMID: 27880062.
5. Cao C, Xiao Z, Wu Y, Ge C. Diet and Skin Aging-From the Perspective of Food Nutrition. Nutrients. 2020 Mar 24;12(3):870. doi: 10.3390/nu12030870. PMID: 32213934; PMCID: PMC7146365.
6. Kramer, R.Z., Bella, J., Mayville, P., Brodsky, B., Berman, H.M. (1999) Sequence-dependent conformational variations of collagen triple-helical structure. Nature Structural and Molecular Biology 6: 454-457.
7. Coad J, Conlon C. Iron deficiency in women: assessment, causes and consequences. Curr Opin Clin Nutr Metab Care. 2011 Nov;14(6):625-34. doi: 10.1097/MCO.0b013e32834be6fd. PMID: 21934611.
8. Bolke L, Schlippe G, Gerß J, Voss W. A Collagen Supplement Improves Skin Hydration, Elasticity, Roughness, and Density: Results of a Randomized, Placebo-Controlled, Blind Study. Nutrients. 2019 Oct 17;11(10):2494. doi: 10.3390/nu11102494. PMID: 31627309; PMCID: PMC6835901.