Purported uses of methionine
Supplement use should be individualized and reviewed by a health care professional such as a registered dietitian, pharmacist, or health care provider. No supplement is intended to treat, cure, or prevent disease.
Methionine is considered an essential amino acid because it must be obtained from the diet. Our bodies cannot produce it.
There are two types of methionine: L-methionine (which occurs naturally and is often found in supplements) and D-methionine. Each contains the same chemical makeup, but the molecules are mirror images. A mixture of the two is called DL-methionine.
Methionine may be beneficial for a variety of health conditions. However, many of these are not well supported by scientific evidence. Here are some of the better supported uses of methionine.
Acetaminophen overdose
One of the main uses of methionine is in the treatment of acetaminophen overdose.
Acetaminophen or Tylenol is a common over-the-counter pain reliever. If a person takes too much acetaminophen, quick action is needed to prevent liver damage and possibly death.
Oral methionine administered over 10 hours has been used to treat acetaminophen overdose. 3-Methionine is thought to prevent acetaminophen by-products from damaging the liver due to acetaminophen overdose.
However, it should be noted that there are other treatment options, and methionine may not be the most effective treatment option for acetaminophen overdose.
cancer risk
Methionine has been studied for its role in cancer risk. However, the results are conflicting.
A 2013 meta-analysis suggested that dietary methionine intake may be associated with a reduced risk of colon cancer. Researchers believe this reduced risk may be due to the role of methionine in the production of S-adenosine methionine (SAMe). Laboratory and animal studies show that SAMe may be able to reduce inflammation, inhibit various cancer pathways, and even cause cancer cell death.
However, these findings have not always been replicated in studies examining the relationship between methionine and cancer. In fact, some studies suggest that limiting methionine intake may reduce the risk of cancer.
A 2020 review noted that methionine is integral to the growth of certain types of cancer cells. According to this review, there is growing evidence that limiting methionine may inhibit cancer cell growth.
More human trials are needed to confirm whether methionine supplementation or methionine restriction is beneficial in reducing cancer risk. Until then, methionine should not be used for this purpose.
liver damage
Methionine may help improve liver damage, especially when used with other treatments.
A recent review examined the role of methionine in liver damage and found that supplementing with methionine may help reduce the risk of liver damage. Methionine supplementation may help increase SAMe levels, thereby preventing liver damage.
However, these findings may be controversial. And, again, stronger research is needed to support this claim.
Other purported uses
Methionine is thought to have other potential benefits, including:
- Nourishes hair, skin and nails
- Slow down cellular aging
- Protect cells from pollutants
- Helps absorb other nutrients such as selenium and zinc
- Helps detoxify heavy metals, including lead and mercury
However, as with many potential uses of methionine, research to support these health claims is limited.
What are the side effects of methionine?
Side effects are always possible when taking supplements, and methionine is no exception. Methionine side effects can range from mild to serious.
Common side effects
Common side effects associated with methionine tend to be mild and include:
- nausea
- Vomit
- drowsiness
- irritability
The best way to avoid side effects as much as possible is to take methionine supplements as directed. Often, side effects are more likely to occur when supplements are taken incorrectly or at too high a dose.
serious side effects
Generally speaking, methionine is considered safe. However, if taken incorrectly, serious side effects may occur. These may include changes in blood pressure, disorientation, and tachycardia, or increased heart rate. 7Although extremely rare, it is possible to overdose on methionine.
Precaution
Methionine may not be safe for everyone. Certain groups of people should avoid using methionine, or at least discuss it with their healthcare provider before taking it.
People with methylenetetrahydrofolate reductase (MTHFR) deficiency, an inherited disorder, should avoid methionine. People with MTHFR deficiency are unable to convert homocysteine, a potentially dangerous compound to methionine. For people with MTHFR deficiency, taking methionine supplements may cause homocysteine levels to be too high.
Likewise, people with high blood levels of homocysteine should avoid methionine supplements. High blood homocysteine can lead to heart disease and other complications.
It has also been suggested that methionine may worsen schizophrenia in some people. However, research on this claim is insufficient. One animal study linked methionine use to behavioral responses and schizophrenia-like symptoms. 10 It is unclear whether these results apply to humans.
There is not enough information to know whether methionine is safe for people who are pregnant or breastfeeding. Therefore, it is recommended to avoid taking it during pregnancy and breastfeeding.
To better understand these and other precautions, talk with your healthcare provider about whether methionine is safe for you.
Dosage: How much methionine should I take?
Always check with your healthcare provider before taking supplements to make sure the supplement and dosage are appropriate for your individual needs.
There is no standard dosage for methionine supplements. However, daily intake of methionine from food and other sources is recommended.
The recommended daily allowance (RDA) for adults is 14 mg/kg of body weight for methionine or cysteine, another sulfur-containing amino acid. Based on this calculation, a 154-pound person needs 1.1 grams of methionine or cysteine per day. You need this amount each day from methionine or cysteine to get all the sulfur your body needs to build important proteins.
The dosage that's right for you may depend on a variety of factors, such as your current health, age, and gender. Be sure to discuss using methionine safely with your healthcare provider.
What will happen if I take too much methionine?
If you take too much methionine, you may suffer from toxicity or even overdose.
Methionine toxicity may cause serious or mild side effects. This may occur over time as methionine builds up or after taking large doses of methionine.
Normal doses of methionine are considered safe for most people. However, according to research, methionine can be toxic in very high doses. Additionally, consuming too much methionine can lead to elevated homocysteine levels, which can lead to heart function problems.
Methionine overdose is extremely rare, but it is possible. In one extreme example, one study participant accidentally took a much higher dose of methionine than he should have. In this case, overdose results in death.
interactive
Interactions with methionine are not well documented. This means we are not aware of any medications or supplements that interact negatively with methionine.
No matter what, it's always best to stay safe.
You can safely read a supplement's ingredient list and nutrition facts panel to find out what ingredients are included and how much of each ingredient is included. Please review this supplement label with your healthcare provider to discuss potential interactions with foods, other supplements, and medications.
How to store methionine
Improper storage of methionine supplements may cause spoilage. Methionine should be stored in a cool, dry place away from direct sunlight. It's best to store methionine supplements in the airtight containers they come with.
Methionine supplements should be discarded once they reach the expiration date listed on the package.
Due to the possibility of overdose, keep methionine supplements out of the reach of pets and small children.
Similar supplements
Some supplements may act similarly to methionine in terms of potential uses. These include:
- Cysteine is the only other amino acid that contains sulfur. Therefore, it may act similarly to methionine. If you've been told you need more sulfur in your diet, you can use methionine or cysteine to do this.
- Methionine may help remove lead from the body, which is what a component of chlorella may also do. 12 However, research surrounding these claims is limited.
If you're not sure which supplement is best for you, talk to your healthcare provider.
Frequently asked questions
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Is methionine safe for babies or children?
Methionine may be safe for infants and children, but check with your child's healthcare provider before use.
Adverse events have not been reported in studies examining the use of methionine in infants and children. 11 However, this research is limited.
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Which food sources have the highest methionine content?
Methionine is found in many foods, making it easy to get everything you need in your diet.
Methionine is most abundant in animal foods, such as beef, poultry, pork, eggs, and seafood. It is also found in plant foods such as nuts, seeds, soybeans, legumes, and some vegetables.
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Do vegetarians need to take methionine supplements to get enough sulfur in their diet?
Since methionine is found in many plant-based foods, vegetarians don't necessarily need to take methionine supplements to get enough sulfur.
If you are a vegetarian (or non-vegetarian), you should only take methionine supplements as directed by your healthcare provider. If you are deficient in methionine, you may need to supplement it, but this is rare.
Sources and precautions of methionine
In most cases, you can get all the methionine you need from food. Methionine is found in many different types of foods, making it easy to add to your diet. Additionally, nutrients in food are often more easily absorbed than nutrients in supplements.
However, some people may need to use methionine supplements for various health reasons.
Food sources of methionine
Methionine is commonly found in many foods. It can be found in vegetarian and non-vegetarian food sources.
Food sources of methionine include:
- Egg
- chicken
- beef
- pork
- milk
- corn
- Lobster (tail)
- Fish (canned tuna)
- oatmeal
- beans
- cauliflower
As you probably know, many of these foods are protein, which makes sense since methionine is used to make protein. Typically, a balanced diet that includes a variety of fruits, vegetables, grains, healthy fats, and lean protein will provide you with all the methionine and other nutrients your body needs.
Methionine supplements
Methionine supplements are available in capsule form. You may also find supplements containing methionine and other nutrients, such as various amino acids. These also tend to be sold in capsule form.
Vegan versions of methionine supplements are available. If you are a vegetarian or vegan, choose a plant-based methionine supplement.
It’s best to choose a methionine supplement that has been certified by a third party, such as the United States Pharmacopeia, NSF International, or Consumer Lab. Since the FDA doesn't regulate supplements as strictly as drugs, certified supplements are more likely to contain the ingredients they claim to contain.
generalize
Methionine is an essential amino acid, which means we must consume it. It is one of only two sulfur-containing amino acids that may help address some health issues. However, research to support most of these health claims is lacking.
There are few side effects from taking methionine, but it is important to take precautions when using it because overdose is possible.
Methionine supplements are not suitable for everyone, so talk to your healthcare provider for more information before starting to take them.
