Top 10 Foods Highest in Cystine (Cysteine)

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Top 10 Foods Highest in Cystine (Cysteine)

Cystine is the oxidized dimer form of the amino acid cysteine, and is considered nutritionally equivalent to cysteine. (3)

Among its many functions, cystine helps create anti-oxidants in the body (1), and can help with hair health. However, none of these claims are well established. (2)

High cystine foods include pork, beef, chicken, fish, lentils, oatmeal, eggs, low-fat yogurt, sunflower seeds, and cheese. (4) The reference dietary intake (RDI) for cystine is 4.1mg per kilogram of body weight or 1.9mg per pound. A person weighing 70kg (~154 pounds) should consume 287mg of cystine per day. (5)

Below is a list of the top 10 foods highest in cystine with the %RDI calculated for someone weighing 70kg (154lbs). For more high cystine foods see the extended list of cystine-rich foods.

List of High Cystine Foods

A pork chop1 Lean Pork Chops
Cystine
in a 6oz Chop
Cystine
per 100g
Cystine
per 200 Calories
595mg
(207% RDI)
350mg
(122% RDI)
359mg
(125% RDI)

More Pork High in Cystine

  • 176% RDI per cup of roast ham
  • 32% RDI per 3oz sausage link
  • 28% RDI per oz of salami

See all meats high in cystine.

A steak on a plate2 Beef (Skirt Steak)
Cystine
per 6oz Steak
Cystine
per 100g
Cystine
per 200 Calories
587mg
(204% RDI)
345mg
(120% RDI)
257mg
(90% RDI)

More Beef and Lamb High in Cystine

  • 126% RDI per 3oz of lamb roast
  • 99% RDI per 3oz buffalo roast
  • 92% RDI per 3oz of beef roast

See all meats high in cystine.

A roast chicken3 Lean Chicken Breast
Cystine
in a 6oz Breast
Cystine
per 100g
Cystine
per 200 Calories
571mg
(199% RDI)
336mg
(117% RDI)
428mg
(149% RDI)

More Poultry High in Cystine

  • 258% RDI per chicken leg
  • 198% RDI in 6oz of ground turkey
  • 125% RDI in a roast chicken thigh

See all meats high in cystine.

Tuna Fillet4 Tuna
Cystine
in a 6oz Fillet
Cystine
per 100g
Cystine
per 200 Calories
546mg
(190% RDI)
321mg
(112% RDI)
349mg
(122% RDI)

More Fish High in Cystine

  • 222% RDI in 20 small clams
  • 175% RDI per 6oz salmon fillet
  • 157% RDI per 6oz tilapia fillet

See all fish and shellfish high in cystine.

Lentils5 Lentils
Cystine
per Cup
Cystine
per 100g
Cystine
per 200 Calories
234mg
(81% RDI)
118mg
(41% RDI)
203mg
(71% RDI)

More Beans High in Cystine

  • 161% RDI per cup of boiled soybeans (edamame)
  • 87% RDI per cup of split peas
  • 68% RDI per cup of chickpeas (garbanzo beans)

See all beans and legumes high in cystine.

A bowl of oatmeal with blueberries6 Oatmeal
Cystine
per Cup
Cystine
per 100g
Cystine
per 200 Calories
227mg
(79% RDI)
97mg
(34% RDI)
273mg
(95% RDI)

More Whole Grains High in Cystine

  • 75% RDI per cup of kamut
  • 51% RDI per cup of whole wheat pasta
  • 32% RDI per cup of rice

See all grains high in cystine.

Eggs7 Eggs
Cystine
in 1 Large Egg
Cystine
per 100g
Cystine
per 200 Calories
146mg
(51% RDI)
292mg
(102% RDI)
377mg
(131% RDI)
Plain yogurt with raspberries8 Low-Fat Yogurt
Cystine
per Cup
Cystine
per 100g
Cystine
per 200 Calories
127mg
(44% RDI)
52mg
(18% RDI)
186mg
(65% RDI)
  • 36% RDI per 16oz glass of milk

See all dairy foods high in cystine.

Sunflower Seeds9 Sunflower Seeds
Cystine
per 1oz Handful
Cystine
per 100g
Cystine
per 200 Calories
109mg
(38% RDI)
383mg
(133% RDI)
132mg
(46% RDI)

More Nuts and Seeds High in Cystine

  • 66% RDI per oz of hemp seeds
  • 40% RDI per oz of chia seeds
  • 36% RDI per oz of cashews

See all nuts and seeds high in cystine.

A slice of swiss cheese10 Swiss Cheese
Cystine
per Oz
Cystine
per 100g
Cystine
per 200 Calories
82mg
(29% RDI)
290mg
(101% RDI)
148mg
(51% RDI)

More Cheese High in Cystine

  • 43% RDI per 1/2 cup of ricotta
  • 30% RDI per oz of gruyere
  • 25% RDI per oz of gouda

See all dairy foods high in cystine.

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A printable list of high cystine foods including pork, beef, chicken, fish, lentils, oatmeal, eggs, low-fat yogurt, sunflower seeds, and cheese.

More Cystine Rich Foods

FoodServingCystine
1 Beef Liver1 slice135% RDI
(388mg)
2 Somen Noodlesper cup69% RDI
(199mg)
3 Teffper cup61% RDI
(174mg)
4 Couscousper cup59% RDI
(168mg)
5 Firm Tofuper cup50% RDI
(144mg)
6 Crab Cakesper cake50% RDI
(143mg)
7 Lima Beansper cup cooked49% RDI
(141mg)
8 Carrotsper cup chopped21% RDI
(60mg)
9 Shiitake Mushroomsper cup cooked14% RDI
(39mg)
10 Almond Butterper tblsp13% RDI
(39mg)

About the Data

Data for the curated food lists comes from the USDA Food Data Central Repository.

You can check our data against the USDA by clicking the (Source) link at the bottom of each food listing.

Note: When checking data please be sure the serving sizes are the same. In the rare case you find any difference, please contact us and we will fix it right away.

About Nutrient Targets

Setting targets can provide a guide to healthy eating.

Some of the most popular targets include:
  • Daily Value (%DV) - The daily value (%DV) is a general guideline for consumption that will prevent deficiency of a particular nutrient in most people. The %DV refers to the percentage of an amount that's found in a single serving of a food. It also accounts for absorption factors. It is set by the U.S. FDA.
  • Recommended Dietary Allowance (%RDA) - The RDA sets an average daily dietary intake level that is sufficient to meet the nutrient requirements of nearly all (97.5%) healthy individuals. It's more specific than the daily value, and varies by age and gender. The RDA is set by the US National Institutes of Health.
  • Reference Dietary Intake (%RDI) -The reference dietary intake is similar to the recommended daily allowance, but is specific to age and gender. The RDI for amino acids is set by the U.N. World Health Organization.
  • Adequate Intake (%AI) - This value is primarily used in reference to omega-3 and omega-6 fats. The Adequate Intake is set by the U.S. Institute of Medicine. Because there is less evidence to determine the ideal targets for consumption of these nutrients, the specific amount is considered to be less reliable. Using the term Adequate Intake, rather than one of the other terms, helps to emphasize that the ideal intake of that particular nutrient has not yet been scientifically determined.

See the Guide to Recommended Daily Intakes for more information.

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Data Sources and References

  1. Mechanisms underlying the cardioprotective effect of L-cysteine. Mol Cell Biochem. 2005 Sep;277(1-2):27-31.
  2. Effects of the Usage of l-Cysteine (l-Cys) on Human Health Molecules. 2018 Mar; 23(3): 575. Published online 2018 Mar 3. doi: 10.3390/molecules23030575
  3. Biochemical and Functional Evaluation of the Intramolecular Disulfide Bonds in the Zinc-Chelating Antimicrobial Protein Human S100A7 (Psoriasin). Biochemistry. 2017 Oct 31;56(43):5726-5738. doi: 10.1021/acs.biochem.7b00781. Epub 2017 Oct 19
  4. U.S. Agricultural Research Service Food Data Central
  5. World Health Organization (WHO) Technical Report Series – Protein And Amino Acid Requirements In Human Nutrition ISBN 978 92 4 120935 9
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