Plant-Based Collagen: Is There Such a Thing as Vegetarian Collagen?

Discover how you can stay vegan while improving your natural beauty with collagen.

plant based collagen 

It probably comes as no surprise that there is truth to the saying "you are what you eat."

When it comes to skincare, the foods, supplements, and powders we consume affect our skin just as much (if not more so!) than the creams and products that we apply on the surface. If you want your skin to maintain the firmness and bounciness of its youth for as long as possible, seeking out the best collagen products and supplements is a no-brainer.

But what if you’ve committed to a vegan lifestyle?

Veganism is becoming increasingly common and popular for many reasons. It's a good option for overall health, a sustainable lifestyle that is better for the environment, and a stand against cruelty to animals.

But when it comes to skincare, you might find yourself wanting to feel the benefits of collagen for your hair, skin, and nails without using beauty products and powders made with ingredients sourced from animals. The very best benefits of collagen include improved skin elasticity, fewer fine lines and wrinkles, and supple, plump, radiant skin – and who doesn't want that?

Since collagen is a protein found in animals and fish, you will find that most collagen products, powders, and liquids are not vegan when you examine the list of ingredients. But is there a plant based collagen available today?

There’s good news and bad news. The bad news is there is currently no such thing as a truly vegan collagen supplement.

The good news? There are alternative ways to incorporate collagen into your life without sacrificing your beliefs or lifestyle. Here’s everything you need to know about the best plant-based and vegan collagen alternatives.

 

Browse our skincare collection & vegan supplements:

https://www.renewalliance.com/collections/all

 

What Is Collagen?

 

Collagen is a protein, the most abundant protein in the entire body (making up about 25% to 35% of the body’s entire protein content). It makes up our joints, bones, tendons, and muscles. It also gives structure to hair, skin, and nails, which is why it’s so often promoted by the beauty industry as one of the very best ingredients in products like moisturizers, serums, powders, drinks, and hair products. You can also think of it as a major building block that can make the body function in different ways, like helping clot blood after an injury and strengthening bones.

Our bodies produce this collagen protein on their own, but the rate of collagen production begins to slowly deteriorate once we pass the age of 30 or so (likely even sooner). This means our skin begins to lose collagen naturally. If we didn’t have any collagen in our skin, it would sag and develop wrinkles – which is what precisely happens as we age because of this gradual loss of collagen from our bodies.

The collagen protein is composed of a triple helix, consisting of two identical chains and a single chain with a slightly different chemical composition. Fibroblasts, a type of biological cell, are the most common cells our body is using to create collagen. They are important in the role of wound healing. Gelatin, which vegans avoid eating, is actually hydrolyzed animal collagen used for various reasons in the food industry. Collagen also has abundant uses in the medical field to help treat issues related to the bones, joints, and skin.

There are at least 16 types of collagen, but types I, II, and III make up between 80% to 90% of the body’s total collagen content. Type I can be found in the skin, nails, bones, tendons, and organs. Type II, on the other hand, forms cartilage. Other types can be found in the hair and placenta. All of these have at least one triple helix. Collagen can be hydrolyzed into peptides so that it is better absorbed by the body when using as a supplement to help treat joint, bone, and skin health.

 

How Is Collagen Made In The Body?

 

Collagen is formed by a combination of two amino acids – glycine and proline. These two amino acids join together and bond with one other amino acid (which can be any of the 17 amino acids) to form triple helix procollagen chains. This process is called collagen synthesis.1

In order for collagen synthesis to happen, your body needs vitamin C, zinc, and copper. These vitamins and minerals are known as cofactors in collagen production, and they work to stabilize and give structure to the enzymes required for collagen synthesis.

Put simply – amino acids plus vitamin C, zinc, and copper equals collagen.

This is why so many skincare products are using amino acids, vitamin C, zinc, and copper as especially effective ingredients for anti-aging effects. They enable us to produce the protein responsible for our skin elasticity. While applying these ingredients topically through our beauty products can make our hair, skin, and nails look and feel good, it is crucial that we also consume these nutrients in our diets through food, supplements, or powders.

Collagen can be degraded or damaged by several factors, including sun exposure, smoking, and the consumption of sugar. Lupus, an autoimmune disorder, can also be damaging to collagen. Conversely, the consumption of certain nutrients and foods can help your body produce collagen to keep skin and joints looking healthy. We will discuss what foods you can eat to support your body to produce collagen a little further on.

vegetarian collagen

 

How Do Collagen Supplements & Powders Work?

 

Collagen supplements are loved by the beauty industry as they can help people feel the benefits of this super protein for healthy hair, skin, and nails, while also impacting other areas like your joints, muscles, bones.

Considering that the process of collagen formation is quite a simple combination of naturally occurring amino acids, vitamins, and minerals, there are plenty of collagen-building powders, pills, and drinks that infuse these ingredients to support your body in its natural collagen production.

These are often available as plant-based collagen options, and they are not to be confused with collagen supplements or powders. Instead, they are merely collagen builders that provide the necessary nutrients for the protein-building process to occur.

There are, however, many collagen products on the market that do contain pre-made collagen peptides. These are available in the form of collagen powder, which is taken orally by dissolving the powder in a glass of water or orange juice. However, a powder product is not absorbed into the body as quickly or effectively as a liquid product.

There are also many liquid collagen supplements available, which can contain high doses of collagen peptides that work to trigger something called a wound repair response in the body. This response kicks your collagen production into motion faster than a powder does, resulting in positive effects for healing and firming up the skin, repairing hair, and strengthening nails.

 

Can Collagen Supplements & Powders Be Vegan?

 

The short answer is no, there is no such thing as vegan collagen powders.

Vegan collagen or vegetarian collagen does not exist because the collagen used in powders and drinks is derived from the connective tissues of animals – for example, in beef, chicken, and pork. There is, however, a marine alternative that is suitable for pescetarian-friendly diets, that has also been shown to be more effective and more sustainable than animal source collagen.

And if you are following a wholly plant-based regime, have no fear, there are vegan collagen-alternative options for you!

Let's take a look at each collagen source, as well as some plant-based options to help you identify the best ways to build collagen and achieve supple, radiant skin while avoiding ingredients derived from animals.

 

Animal-Based Collagen

 

Animal collagen is derived from three main sources; chicken, porcine, or bovine.

The animal-based collagen that comes from chicken or pig is typically sourced from the skin, tendons, and cartilage of the animal, and it contains mostly type II collagen which is beneficial for our joints and tendons, but less so for our skin.

Bovine collagen is sourced from the bones of cows, bison, antelopes, or yaks, most typically extracted by boiling the bones and turning the resulting collagen ingredients into a collagen powder supplement. Animal collagen powder supplements can be dissolved into a glass of water or juice. Some people also make their own collagen beauty broth at home by boiling beef bones into a soup. Bovine collagen is primarily composed of types I and III collagen and it is beneficial for skin health.

However, there are some concerns about sustainability and bovine collagen powders, drinks, and broths. Since bovine collagen relies on cattle farming, which in turn results in significant greenhouse gas emissions, it is not the most eco-friendly option available on the market.

Animal-based collagen ingredients, while generally safe, have also been related to a risk of contamination and inflammatory issues.

 

Marine-Based Collagen

 

Marine-based collagen is a great alternative to animal collagen for meat-eaters and pescetarians alike as it is more sustainable and it also has the upper hand in something known as bioavailability.

Bioavailability is the rate at which a food or supplement is absorbed through the intestinal wall, and the nano-sized molecules of marine collagen give it a higher bioavailability than that of animal collagen.

Why does bioavailability matter? The higher bioavailability of marine collagen means that it is more effective at reaching your bloodstream quickly and intact, and is, therefore, the most effective source of collagen peptides that your body can put to use straight away for healing your hair, skin, and nails.

Marine-based collagen is sourced from the scales of cold sea fish such as red snapper, and it is using parts of the fish that are typically discarded, making it a sustainable, waste-reducing alternative to animal-based collagen. It contains mostly type I and type II collagen, making it beneficial for our hair, skin, nails, joints, and muscles.

Marine-based collagen is often available in the form of a liquid collagen supplement, but it can also come as a collagen powder or an ingredient in a topical beauty product.

 

More helpful reading:

https://www.renewalliance.com/blogs/i/marine-collagen-for-skin-rejuvenation

 

Plant-Based & Vegan Collagen

 

Unfortunately, there is no such thing as "vegan collagen" or "plant collagen". Collagen is a protein that has a unique amino acid formation that cannot be found in plants. It can only be sourced from animal products or marine sources.

While you will be happy to hear that there is technically a way to produce plant-based collagen and vegan collagen products from genetically modified bacteria and yeast (yay!), these beauty supplements and powders are not yet widely available. We may have to wait a long time before these plant-based collagen supplements are fully developed and tested with adequate results, but until then, there are some other vegan collagen-building options that we can look to.

Instead of promoting a collagen-containing product, powder, or drink, vegan companies will often promote a “collagen builder,” which contains a combination of amino acids, vitamins, and minerals designed to support your body's collagen production without the use of ingredients derived from animals.

These plant-based "collagen" supplements are focused on the cofactors of collagen, providing collagen building blocks rather than collagen itself. Through their collagen-building protein and vitamin content, they can mimic the effects of a marine or animal collagen supplement by kicking your body's collagen synthesis process into action.

However, all of the ingredients typically found in these plant-based collagen builders can just as easily be obtained through a healthy plant-based diet. For vegans, the best way to have a collagen drink alternative is to supplement your lifestyle with actual food sources that build and produce collagen in the body, allowing you to feel the benefits of collagen without using ingredients related to animals.

 

10 Ways To Boost Collagen Naturally With a Plant-Based Diet

 

According to Dr. Elizabeth Bradley of the Cleveland Clinic, one of the main reasons people don't have enough collagen is poor nutrition.2

The good news for anyone following a vegan or plant-based lifestyle is that you can support your body's collagen production by providing the right building blocks through your food intake.

Here are the 10 best foods and plant-based collagen-alternative supplements that can boost your body's collagen production and prevent collagen damage and degradation. Ultimately, this can ensure your skin is looking its best with a minimal amount of wrinkling and sagging, while also keeping your bones and joints healthy, and preventing pain.

 

1. Amino Acids

 

As we have learned from the collagen synthesis process, amino acids are the building blocks of collagen. The primary natural collagen builders are glycine, lysine, proline, which are commonly found in animal products, but they can also be obtained in a plant-based diet from beans and legumes.

Chickpeas, lentils, peas, kidney beans, black beans, soybeans, and pinto beans are all excellent sources of protein, as you most likely already know. But more specifically, you should be aware that these are excellent sources of the amino acids glycine and lysine, each of which is a collagen-building protein. Proline is a little harder to source in plant-based products, but this collagen-building protein can be found in mushrooms, asparagus, cabbage, and alfalfa sprouts.3

It’s important to incorporate plant-based collagen-building protein in the form of amino acids into your meal plan as often as you can, in order to support healthy hair, skin, nails, joints, and muscles.

 

2. Plant Proteins

 

Plant proteins can be found in the aforementioned beans and legumes. A few other options include quinoa, chia seeds, potatoes, kale, broccoli, mushrooms, hemp seeds, and nuts like almonds and peanuts. A plant-based collagen-building protein can be incorporated into all kinds of recipes and dishes, ensuring you don’t get bored with your food choices while also getting all the necessary protein to keep your body functioning at a high level.

If you’ve been vegan for a while, these foods are most likely nothing new for you and you’ve been eating them for a long time. If you’re new to being vegan, you can see how there are plenty of plants that can provide you with collagen-building protein with no need to eat animal products ever again.

According to registered dietician Cynthia Sass, it is entirely possible to get enough protein in our diets without meat. While we are taught from a young age that our bodies require meat, the reality is that the same essential nutrients and protein can be obtained from plants.4

By consuming plenty of plant-based proteins in your meals, you can provide all of the collagen-building protein needed to achieve the radiant, plump skin you might be seeking from a vegan collagen supplement.

plant collagen

 

3. Vitamin C

 

Vitamin C is a water-soluble vitamin that is not naturally produced by the body and it is, therefore, essential to include it in our diets every day.

Vitamin C is a plant-based collagen builder, essential for healthy hair, skin, and nails as well as our immune function. It is a cofactor in collagen production, and without it, our skin would just fall apart. Vitamin C regulates the synthesis of collagen and is found in both the epidermis and the dermis. However, it also begins to decrease with age.

Luckily, a plant-based lifestyle ensures you’ll get plenty of vitamin C and truly feel the benefits for your skin. But, you can also take a vitamin C supplement product, powder, or drink to support your intake if needed.

Vitamin C is found in citrus fruits like lemons, tangerines, and oranges, as well as in green or orange peppers, kiwi, papaya, cauliflower, cantaloupe, tomato, strawberries, and sweet potato. With such an abundance of sources, a deficiency is rare in any plant-based diet. .5

For a direct hit of vitamin C for your face, topical application via a moisturizer or serum is also an effective way of increasing vitamin C levels in the skin and this can boost collagen production as well.

Look out for vitamin C in skincare serums and lotions as a great vegan collagen-alternative to products derived from animals.

 

4. Zinc

 

Zinc is one of the best ingredients to look out for when building your vegan collagen-building meal plan.

Zinc is another cofactor of collagen, a mineral responsible for collagen synthesis as well as a whole array of other enzyme functions in the body. Zinc can also support a healthy metabolism and immune system. Luckily, we can obtain all the zinc our bodies need through our diets!

The highest concentration of zinc is typically found in red meat and some seafood like oysters, crab, and lobster. Thankfully, zinc can also be obtained in a vegan diet through chickpeas, cashew nuts, sunflower seeds, pumpkin seeds, whole grains, and fortified breakfast cereals. If you are following a plant-based lifestyle that includes dairy products, you can get your fix of zinc from milk and cheese too.

 

5. Copper

 

Copper is another mineral essential to collagen production, elastin production, and the regulation of melanin levels in the skin. These three components make copper one of the essential nutrients for supple, flexible skin with healthy pigmentation. Copper is also essential to our overall health, regulating cholesterol levels, boosting our immune system, and contributing to healthy fetus development in the womb.

Copper is a micronutrient that we need to get from our food in small amounts every day as our bodies cannot store it. It is especially essential for any plant-based collagen-building meal plan.

The best plant-based sources of copper include sunflower seeds, almonds, cashews, sesame seeds, shiitake mushrooms, and leafy green vegetables. Copper is also available as a dietary supplement in the form of a powder or pill, if you would like to boost your intake.

 

6. Marine Ingredients

 

Sea plants like algae are also a great way to support skin collagen because they are composed of proteins and amino acids, among other substances. Clinical studies have shown that the antioxidant properties of algae can improve skin quality, making it look more youthful by preventing collagen degradation.

Antioxidants are natural enemies to free radicals, which are unstable atoms that attack cells throughout the body. In the skin, they damage collagen and cause the skin to sag and wrinkles to form. With antioxidants, some or all of this damage can be prevented or countered.6

Spirulina is a type of blue algae that has shown promise in helping to prevent common signs of aging like wrinkles and fine lines, and it is becoming increasingly common in the list of ingredients of beauty products and powders. A type of green algae called chlorella has also shown similar promise with beauty benefits for the skin. Algae typically work as antioxidants, but can also provide hydration benefits to keep the skin looking smooth and relaxed without any lines.7

collagen plant based

 

More helpful reading:

https://www.renewalliance.com/blogs/i/algae-for-skin

 

7. Carotenoids

 

Carotenoids are red, orange, and yellow pigments in plant-based foods, giving color to foods like carrots, bell peppers, corn, tomatoes, and pumpkins. Some carotenoids function as provitamin A, which means that they can be converted to vitamin A in the body.

Carotenoids are powerful antioxidants, functioning to fight against free radical damage in the body and protect your collagen from degradation. They are also important for eye health, heart health, and our immune systems.

Beta-carotene is a carotenoid that functions as provitamin A and is shown to help protect the skin from UV radiation and sun damage. Beta-carotene can be found in many plant-based foods such as carrots, sweet potatoes, broccoli, and dark leafy greens like kale, spinach, and chard.8

Lycopene does not convert to vitamin A in the body, but it is still an important carotenoid to include in our diets. Lycopene is a very potent antioxidant with astringent and anti-inflammatory properties, which is great for reducing the appearance of pores, reducing redness, and creating a bright, even skin tone. Tomatoes have the highest concentration of lycopene available in any food source, so they truly are a boon for our skin. Other sources of lycopene include watermelon, pink grapefruit, and papaya.

Carotenoids are fat-soluble compounds, which means that they need fat to fully absorb in the body. It's best to combine your carotenoid intake with some healthy plant-based fats such as avocado, olive oil, nuts, and seeds, supporting a healthy and nutritious vegan collagen-building lifestyle without using ingredients related to animals.

 

8. Ginseng

 

Studies have shown that ginseng can help boost collagen production in the skin, making it a great plant-based collagen alternative for aging individuals who are starting to see signs of wrinkling and sagging on their bodies. Ginseng also boosts fibroblast production, which in turn helps increase the amount of collagen in the body. Moreover, Korean red ginseng shows antioxidant activity that can further help prevent collagen damage and degradation.9

Ginseng is a root that is extremely popular in Asian traditional medicine. It has anti-inflammatory properties that can help address a variety of health issues, seeing as inflammation is often the root cause of many health concerns. You can take ginseng in an oral supplement product or powder, but it’s also available as an active ingredient in a variety of topical beauty treatments, particularly from Korean skincare brands.

 

9. Antioxidants

 

Yep, antioxidants are a big deal. That’s because they neutralize free radicals, which are pretty much bombarding us constantly. Free radicals are unstable molecules that damage our cells, breaking down our skin's collagen resulting in blemishes such as wrinkles, dark spots, uneven skin tone, and sagging skin.

Antioxidants work to neutralize these free radical molecules, protecting our cells and our collagen production as a result. Even better, antioxidants don’t just prevent skin aging, but they prevent cell damage throughout the body, helping to protect against various diseases.

Basically, we need antioxidants to keep free radical damage at bay so we can look and feel our best.

Antioxidants can be found in abundance in plant-based diets, and we have already mentioned some of the main sources of vitamin C and vitamin A which are packed with free-radical-busting antioxidants. Flavonoids, catechins, and phytoestrogens are some other antioxidants to be aware of, and these can be found in dark chocolate, red grapes, goji berries, green tea, and matcha powders.

French pine bark is a particularly great antioxidant and anti-inflammatory product thanks to its high polyphenol content. Polyphenols are micronutrients found in plant-based foods that have major antioxidant power. Studies have shown that French pine bark consumption specifically helps reduce signs of skin aging.10

 

Fight Free Radicals With Taut's Masquelier French Pine Bark OPC

 

The good news is that you can boost your body's antioxidants and give your collagen production its best chance at survival by using a plant-based antioxidant supplement.

Taut's LAC Masquelier French Pine Bark OPC is a great choice as a plant-based collagen alternative because it fights free radicals, prevents collagen and elastin damage, improves skin suppleness, and helps reduce the appearance of wrinkles for an overall smoother complexion.

As one of nature’s most powerful antioxidants, it also protects and strengthens your vascular system and enhances maximum blood flow and waste removal throughout your body.

Tests have shown Masquelier's French Pine Bark supplement to be significantly more powerful than vitamin E and 20 times more powerful than vitamin C as an antioxidant.

This supplement is 100% vegan, making it the perfect alternative to animal-based collagen products.

 

10. Hyaluronic Acid

 

Our final tip for a plant-based collagen alternative is hyaluronic acid, another superstar ingredient you can rely on to improve your skin’s appearance from the inside out. Hyaluronic acid is a natural substance also found in the body – much like collagen – that helps cushion joints, gives eyeballs their shape, and keeps skin plump and youthful.

Its main function is to retain water so that it can keep tissues in your body lubricated. This lubrication accounts for ease of movement in the joints and gives the skin its youthful plumpness.

You might have guessed that like collagen and vitamin C, hyaluronic acid also deteriorates with age. This is where supplementation can be highly effective, and luckily, there is such a thing as vegan hyaluronic acid – one of the best plant-based collagen alternatives.11

 

Experience The Benefits Of Vegan Hyaluronic Acid With Taut Hydrate

 

Taut Hydrate is a hyaluronic acid supplement that is great for dry and dehydrated skin that needs a boost. It features plant-based hyaluronic acid and grape seed extract that works as a duo to plump up the skin and improve overall firmness and hydration, with visible results for your whole body.

It's one of the closest things to vegan collagen available, mimicking the effects of collagen supplements with an entirely plant-based formula!

Our plant-derived pills work like a super-moisture magnet for your skin. Made with 99% pure hyaluronic acid, Taut Hydrate will fill, hydrate, and plump up your skin from deep within, where serums and fillers cannot penetrate.

Grape seed extract acts as a powerful antioxidant, protecting skin from free radical damage, reducing imperfections, and achieving that amazing glow you’ve been looking for.

Our all-natural, 100% vegan, gluten-free, and non-GMO formula is a great plant-based way to replenish moisture, increase elasticity, and keep fine lines and wrinkles at bay.

With these 10 plant-based sources of antioxidants, you can boost collagen in your body and help improve overall skin quality, reducing the appearance of wrinkles and fine lines, firming and toning skin so that it’s less likely to sag, and even improving overall tone for a more even look.

Although a vegan collagen product may be on the horizon, you don’t have to wait years to reap its rewards when there’s so much you can do yourself by incorporating these foods and ingredients into your diet and skincare routine. You'll feel the results in your skin, hair, and nails in no time!

 

Finally, Don't Forget To Protect Your Skin From Cellular Damage

 

As well as seeking out plant-based collagen alternatives, there are other ways you can help your body's collagen.

While supplementing with vegan collagen or a plant-based collagen builder is a step in the right direction towards healthy, radiant skin, it is also extremely important to protect your existing collagen levels with a healthy lifestyle that avoids bad habits.

We all know that too much sugar, excessive alcohol, and too many cigarettes, will have negative impacts on our health, but did you know that these bad habits can also wreak havoc and destroy your collagen?

These toxins in our diets and our environments create an abundance of free radicals in our bodies, causing damage at a cellular level that will deplete our collagen supplies and lead to many other major health issues over time.

So our final tips for your plant-based collagen-friendly lifestyle are to: Avoid the harsh sun, stop smoking tobacco, and keep your alcohol and sugar consumption to a minimum.

We always believe that prevention is better than cure, and with a healthy, plant-rich vegan meal plan and skincare routine you are already well on your way to providing the antioxidants your body needs to stave off the damage related to these habits.

But why not give your skin an extra chance at radiance by using a free-radical-busting supplement?

 

Rejuvenate Tired, Dull Skin With A Plant-Based Antioxidant Formula

 

If your skin is feeling the unpleasant results of sun damage, stress, cigarettes, or pollutants, you're not alone. It's probably the reason you're looking for a plant-based collagen alternative in the first place. 12

Even with a healthy diet, the reality is that our skin deteriorates over time, with environmental toxins and dietary factors contributing to collagen degradation and excess melanin production.

This excess melanin can cause hyperpigmentation, dull and uneven skin tone, and age spots. These imperfections are a sign of too much toxic waste building up in the liver, a by-product of free radical damage throughout our lives.

A plant-based supplement like Taut Bright works to brighten the skin and reverse these signs of aging with a detoxifying, antioxidant formula. It contains 7 active ingredients that work to minimize cellular damage caused by free radicals, inhibit melanin production, reduce dark spots and pigmentation, and naturally lighten skin. 

The hero ingredient of Taut Bright is L-Glutathione, the mother of all antioxidants which works to detoxify cells and boost the immune system. Vitamin C works as a collagen builder to help your body produce collagen, while L-Cysteine is an important amino acid and antioxidant that can also help reduce inflammation.

Our 100% vegan formula works to minimize the effects of free radical damage, using powerful antioxidants to detoxify the liver and reduce oxidative stress throughout the body. It's the perfect vegan collagen alternative for damaged, dull skin.

The results? Visibly faded age spots, and radiant, luminous, bright skin that stands the test of time.

So there you have it. Although vegan collagen powders and plant-based collagen products are not yet tested and available today, there are plenty of steps you can take to feel the benefits of collagen for your skin, hair, nails, joints, and bones – using plants and plants alone!

Have questions? Get in touch with our team and they'll be happy to help you on your quest to achieving radiant skin!

 

References:

  1. https://www.ncbi.nlm.nih.gov/books/NBK21582/
  2. https://health.clevelandclinic.org/the-best-way-you-can-get-more-collagen/
  3. https://atpscience.com/hydroxyproline-the-missing-element-for-vegans/
  4. https://www.nbcnews.com/better/lifestyle/ask-nutritionist-what-are-best-sources-plant-based-protein-ncna982496
  5. https://lpi.oregonstate.edu/mic/health-disease/skin-health/vitamin-C
  6. https://pubmed.ncbi.nlm.nih.gov/28770671/
  7. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6266229/
  8. https://academic.oup.com/ajcn/article/96/5/1179S/4577133
  9. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3659568/
  10. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3426262/
  11. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5522662/
  12. https://www.nia.nih.gov/health/skin-care-and-aging