15 Foods High in Glycine: Benefits, Sources, and Daily Requirements

Glycine is a vital amino acid that plays numerous essential roles in your body, from building proteins and supporting collagen production to promoting better sleep and reducing inflammation. While your body can produce some glycine on its own, research suggests that you may not make enough to meet all your needs, making dietary sources increasingly important.

This comprehensive guide explores the top foods high in glycine, their health benefits, and how much you need daily to support optimal health.

What Is Glycine and Why Do You Need It?

Glycine is classified as a non-essential amino acid, meaning your body can synthesize it from other amino acids, particularly serine. However, emerging evidence indicates that internal production may be insufficient for all bodily functions, making dietary intake important.

This amino acid is the smallest and simplest of all amino acids structurally, yet it performs numerous critical functions:

• Serves as a building block for proteins, especially collagen
• Acts as a neurotransmitter in the central nervous system
• Supports the production of glutathione, a powerful antioxidant
• Plays a role in metabolic regulation and nutrient processing
• Helps regulate blood sugar levels
• Supports healthy sleep patterns
• Aids in tissue repair and wound healing

Top 15 Foods High in Glycine

The richest dietary sources of glycine come primarily from animal proteins, particularly those containing collagen. Here are the top foods to incorporate into your diet:

1. Gelatin Powder

Gelatin is the absolute champion when it comes to glycine content, providing approximately 19 grams per 100 grams (3.5 ounces). Derived from animal collagen, gelatin is an excellent way to boost your glycine intake through homemade bone broth, gelatin desserts, or as a supplement.

2. Pork Skin and Rinds

Pork skin contains about 11.9 grams of glycine per 100 grams. Pork rinds or crispy pork skin snacks are popular options, though they should be consumed in moderation due to their fat content.

3. Bone Broth

While exact amounts vary depending on cooking time and ingredients, bone broth made from chicken, beef, or pork bones is exceptionally rich in glycine. Slow-cooking bones for 12-24 hours releases collagen that breaks down into gelatin and amino acids including glycine.

4. Chicken Skin

Chicken skin provides approximately 3.3 grams of glycine per 100 grams. While often removed for dietary reasons, the skin is actually one of the most glycine-rich parts of the chicken.

5. Sesame Seeds and Sesame Flour

Low-fat sesame flour contains about 3.4 grams of glycine per 100 grams, making it one of the best plant-based sources. Sesame seeds themselves also provide significant amounts.

6. Pork Chops and Tenderloin

Pork meat, particularly cuts with connective tissue, provides good amounts of glycine along with other essential amino acids and nutrients.

7. Dried Egg Whites

Egg white powder contains approximately 2.8 grams of glycine per 100 grams, making it a versatile protein source for smoothies and baking.

8. Bacon

Bacon provides about 2.6 grams of glycine per 100 grams. While it’s a good source, it should be consumed in moderation due to its sodium and saturated fat content.

9. Beef (All Cuts)

Lean beef contains approximately 2.2 grams of glycine per 100 grams. Tougher cuts with more connective tissue typically contain higher amounts.

10. Cuttlefish and Squid

These seafood options provide about 2.0 grams of glycine per 100 grams, along with other beneficial nutrients like protein and minerals.

11. Lamb

Lamb meat contains approximately 1.8 grams of glycine per 100 grams, with variations depending on the cut.

12. Turkey

Both light and dark turkey meat provide good amounts of glycine, with skin-on portions offering higher concentrations.

13. Fish with Edible Skin

Salmon, mackerel, and other fish species with edible skin provide glycine, particularly when the skin is consumed.

14. Collagen Supplements

While technically a supplement rather than a food, collagen peptides or hydrolyzed collagen are excellent concentrated sources of glycine and can be easily added to beverages and foods.

15. Dairy Products

Cheese, yogurt, and milk contain modest amounts of glycine, with harder aged cheeses typically providing more than softer varieties.

Plant-Based Sources of Glycine

While animal products are the richest sources, some plant foods also contain glycine:

• Legumes: Soybeans, lentils, and beans provide moderate amounts
• Seeds: Pumpkin seeds, sunflower seeds, and sesame seeds
• Nuts: Almonds, pistachios, and peanuts
• Spirulina: This blue-green algae contains notable amounts of various amino acids
• Seaweed: Certain varieties provide glycine along with other nutrients

However, plant sources generally contain significantly less glycine than animal sources, particularly those rich in collagen.

Health Benefits of Glycine

Supports Collagen Production

Glycine accounts for approximately one-third of the amino acids in collagen, making it essential for maintaining healthy skin, joints, bones, and connective tissue. Adequate glycine intake supports skin elasticity, joint mobility, and tissue repair.

Improves Sleep Quality

Research has shown that glycine supplementation before bedtime can improve sleep quality, reduce the time it takes to fall asleep, and enhance daytime alertness. It works by lowering core body temperature and exerting calming effects on the brain.

Protects Against Muscle Loss

Glycine helps preserve muscle tissue during catabolic conditions and supports muscle protein synthesis, making it valuable for active individuals and older adults concerned about age-related muscle loss.

Supports Metabolic Health

This amino acid plays a role in glucose metabolism and insulin sensitivity. Some studies suggest that higher glycine levels are associated with better metabolic health and reduced risk of type 2 diabetes.

Promotes Antioxidant Production

Glycine is a precursor to glutathione, one of the body’s most important antioxidants. Adequate glycine intake supports glutathione production, helping protect cells from oxidative stress and damage.

Aids Digestive Health

Glycine helps protect the gastrointestinal lining and may support the healing of digestive issues. It’s also involved in the production of bile acids necessary for fat digestion.

Supports Healthy Inflammatory Response

Research indicates that glycine has anti-inflammatory properties and may help modulate the immune system’s response to injury or stress.

How Much Glycine Do You Need Daily?

While there’s no official recommended daily allowance (RDA) for glycine, research suggests that most people synthesize about 3 grams of glycine per day internally. However, studies estimate that the body’s total requirement may be around 10-12 grams daily for optimal health, particularly for collagen synthesis.

This means you may need to obtain approximately 7-9 grams of glycine from dietary sources to meet your body’s needs fully. However, requirements can vary based on:

• Age (older adults may need more for collagen maintenance)
• Activity level (athletes may require higher amounts)
• Health status (injury or illness may increase needs)
• Dietary patterns (diets low in collagen-rich foods may require supplementation)

Glycine vs. Methionine Balance

An important consideration when discussing glycine intake is its relationship with methionine, another amino acid abundant in muscle meat. Some researchers suggest that modern diets may contain too much methionine relative to glycine, potentially creating an imbalance.

Muscle meat (like chicken breast, steak, and pork loin) is high in methionine but relatively low in glycine. During metabolism, methionine is converted to homocysteine, and adequate glycine intake may help process homocysteine more efficiently.

To maintain a healthy balance:

• Include glycine-rich foods alongside muscle meats
• Consume whole animals when possible, including skin, bones, and connective tissue
• Make bone broth regularly
• Consider collagen supplementation if your diet lacks these foods
• Ensure adequate intake of B vitamins (folate, B6, B12) which help process homocysteine

Tips for Increasing Glycine Intake

Make Bone Broth at Home

Simmer chicken, beef, or pork bones with vegetables and apple cider vinegar for 12-24 hours. The long cooking time extracts collagen and gelatin, providing abundant glycine. Use the broth as a base for soups, stews, or sip it alone.

Don’t Discard Chicken Skin

Instead of removing and discarding chicken skin, cook it until crispy and enjoy it as part of your meal for a glycine boost.

Choose Tougher Cuts of Meat

Less expensive cuts like chuck roast, short ribs, shanks, and oxtail contain more connective tissue and therefore more glycine. Slow cooking makes them tender and delicious.

Add Gelatin to Your Diet

Unflavored gelatin powder can be added to smoothies, oatmeal, soups, and sauces. You can also make healthy gelatin desserts using fruit juice and gelatin.

Try Collagen Supplements

Collagen peptide powders dissolve easily in both hot and cold liquids and are flavorless, making them convenient for adding to coffee, tea, smoothies, or water.

Eat Whole Fish

When eating fish like salmon or sardines, consume the skin, which contains concentrated collagen and glycine.

Include Organ Meats

Liver, heart, and other organ meats provide glycine along with numerous other nutrients often lacking in muscle meat alone.

Who May Need More Glycine?

Certain groups may benefit from paying special attention to glycine intake:

• Older adults: Collagen production naturally decreases with age, increasing glycine requirements for maintaining skin, joint, and bone health
• Athletes and active individuals: Higher protein turnover and tissue repair needs may increase glycine requirements
• People with joint issues: Those with arthritis or joint pain may benefit from increased glycine for collagen synthesis
• Individuals with sleep problems: Glycine’s sleep-promoting effects may help those struggling with sleep quality
• Those eating primarily muscle meat: Diets high in muscle meat but low in collagen-rich foods may create a methionine-glycine imbalance
• Vegetarians and vegans: Plant-based diets naturally contain less glycine, making supplementation worth considering

Potential Concerns and Considerations

Is Too Much Glycine Harmful?

Glycine is generally considered very safe, even at high doses. Studies using up to 90 grams per day have found no serious adverse effects. Some people may experience mild digestive upset at very high doses, but this is uncommon with dietary intake.

Food Quality Matters

When consuming animal products for glycine, choose high-quality sources when possible. Grass-fed, pasture-raised, and wild-caught options typically provide better nutrient profiles and fewer contaminants.

Balance Is Key

While increasing glycine intake can be beneficial, it should be part of a balanced diet rich in various nutrients. Don’t rely solely on one or two foods; aim for variety.

Supplementation Considerations

If you’re considering glycine or collagen supplements, consult with a healthcare provider, especially if you have existing health conditions or take medications. While generally safe, it’s always wise to seek professional guidance.

Glycine-Rich Recipe Ideas

Classic Bone Broth

Combine bones, vegetables (onions, carrots, celery), herbs, and a splash of apple cider vinegar in a large pot or slow cooker. Simmer for 12-24 hours, strain, and enjoy. Each cup provides several grams of glycine.

Collagen-Boosted Smoothie

Blend your favorite fruits with collagen peptides or gelatin powder for a glycine-rich breakfast or snack.

Gelatin Gummies

Mix fruit juice with gelatin powder according to package directions, pour into molds, and refrigerate for a healthy, glycine-rich treat.

Slow-Cooked Short Ribs

Braise beef short ribs with vegetables and broth for tender, fall-off-the-bone meat rich in glycine and other nutrients.

Chicken Pho

This Vietnamese soup made with long-simmered bone broth provides substantial glycine along with herbs, vegetables, and rice noodles.

The Bottom Line

Glycine is an important amino acid that supports numerous bodily functions, from collagen production and tissue repair to sleep quality and metabolic health. While your body can produce some glycine internally, dietary sources are likely necessary to meet your total needs.

The richest sources of glycine come from collagen-containing animal products, particularly bone broth, gelatin, skin, and connective tissue. Including these foods regularly in your diet can help ensure adequate glycine intake, especially when balanced with muscle meat consumption.

For those who don’t consume animal products or struggle to get enough glycine-rich foods, collagen or glycine supplements may be worth considering after consulting with a healthcare provider.

By incorporating a variety of glycine-rich foods into your regular eating pattern, you can support your body’s collagen production, optimize sleep quality, and promote overall health and wellness.

Sources:

• USDA FoodData Central – Food Composition Database
• National Institutes of Health – PubMed Central
• NIH Office of Dietary Supplements
• USDA Food and Nutrition Information Center
• Oxford Academic Journals – Nutrition Research
• British Journal of Nutrition