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Methionine is an essential amino acid — one of the building blocks of protein that cannot be produced by the human body so must come from our food. It is one of two sulfur-containing amino acids (the other is cysteine). Methionine is an intermediary in the synthesis of cysteine, carnitine, taurine, and other compounds. It protects liver cells, and helps to prevent lipid peroxidation, and possibly atherosclerosis and elevated cholesterol. Although methionine is essential to human life, some people benefit by limiting, but not eliminating methionine in their diets. For such individuals a methionine-restricted diet may be advised.

 

Should I be on a methionine-restricted diet?

Some individuals need to restrict methionine due to inherited disorders that affect methionine metabolism. There is growing interest in methionine restricted diets for those who are unaffected by these genetic metabolic disorders. Evidence suggests that such diets could enhance longevity and help to prevent or treat certain chronic health conditions. The most common indications for a methionine-restricted diet are:

 

i) MTHFR variants. MTHFR gene mutations can lead to elevated homocysteine. Methionine restriction is commonly recommended to help reduce homocysteine accumulation.

 

ii) Cancer. While human studies are sparse, there is some evidence that cancer cells grow less robustly, and sometimes undergo apoptosis (cell death) when deprived of methionine.

 

iii) Depression. High methionine intakes can elevate homocysteine levels and risk of depression.

 

iv) Lifespan extension. Low methionine diets increase metabolic flexibility and overall insulin sensitivity and improve lipid metabolism while decreasing systemic inflammation.

 

v) Insulin resistance. Methionine restriction has been shown to reduce adiposity and improve insulin sensitivity.

 

vi) Homocystinuria. This inherited disorder of metabolism often requires a low methionine diet.

 

If methionine-restriction may help kill cancer cells and increase longevity, shouldn’t everyone be on a methionine-restricted diet?

We don’t know for sure, but it is an option for those who are interested in employing a novel dietary strategy for disease risk reduction. While severe methionine restriction is rarely advised, a moderate methionine restriction may be beneficial. The most concentrated methionine sources are animal products such as meat, poultry and fish. You will see from the table below that the eating pattern that is lowest in methionine is a purely plant-based diet or vegan diet. Other vegetarian or near-vegetarian diets are lower in methionine than omnivores diets, but not as low as vegan diets. For most people, simply eating a plant-based diet is likely sufficient for reducing methionine intake. Those with metabolic disorders or other conditions that may warrant methionine restriction can further restrict methionine by limiting high methionine plant-based foods.

 

If a methionine restricted diet is indicated for me, how much methionine should I be eating each day?

The RDA (recommended dietary allowance) for methionine + cysteine (adults 19 yrs+) is 19 mg/kg/day, while the EAR (estimated average requirement) is 15 mg/kg/day. People should not dip too much below these levels as they represent the lower end of what is needed for human health. Methionine-restricted diets allow 800-1200 mg methionine per day for most adults. For methionine alone, 15 mg/kg is thought to be a reasonable lower limit. So, if a therapeutic, methionine-restricted diet is indicated for you, multiply your healthy body weight by 15 to find a level of methionine intake that is appropriate. Let’s say your healthy body weight is 60 kg, you would need 900 mg methionine per day.

 

Are there any downsides to severely restricting methionine?

Absolutely. There is some evidence that a lack of methionine could reduce levels of S-Adenosylmethionine or SAM-e increasing risk of depression. A lack of methionine has also been linked to senile graying of hair. When you restrict methionine you are naturally restricting protein, at least to some degree.  Ensuring sufficient protein is essential to health. Protein is necessary for building, strengthening and repairing body tissues, for making antibodies, hormones, enzymes and other compounds that are critical to every body process.  A lack of protein can result in muscle loss, increased risk of bone fractures and undesirable changes in hair and skin. Seniors tend to absorb protein less efficiently, so they may need to consume 15-25% more protein than other adults in order to absorb the same amount. So while methionine restriction can be beneficial, it is important that we meet our needs for methionine, and for protein.

 

 

METHIONINE IN COMMON FOODS

(SOURCE: THE USDA NUTRIENT DATABASE RELEASE 28)

 

 

Methionine (mg/serving)

0-50 mg

51-100 mg

101-150 mg

151-200 mg

201-250 mg

251-300 mg

301+ mg

 

 

Vegetables

Weight

Measure

Methionine (mg)

Asparagus, cooked

180 g

1 cup

50

Green beans, cooked

125 g

1 cup

29

Yellow beans, cooked

135 g

1 cup

24

Beets, cooked, sliced

170 g

1 cup

32

Broccoli rab, raw, chopped

40 g

1 cup

19

Broccoli, raw, chopped

91 g

1 cup

35

Burdock root, raw

118 g

1 cup

11

Cabbage, chinese, cooked, shredded

179 g

1 cup

15

Cabbage, cooked

150 g

1 cup

9

Carrots, raw, chopped

128 g

1 cup

26

Cauliflower, raw, chopped

107 g

1 cup

21

Celery, raw, chopped

101 g

1 cup

5

Chard, swiss, raw

36 g

1 cup

7

Chard, swiss, cooked

175 g

1 cup

35

Collards, raw

36 g

1 cup

12

Collards, cooked

170 g

1 cup

68

Cucumber, raw

104 g

1 cup

6

Eggplant, cooked

99 g

1 cup

9

Endive, raw

50 g

1 cup

8

Kale, raw, chopped

67 g

1 cup

18

Kale, cooked

130 g

1 cup

23

Kohlrabi, raw

135 g

1 cup

18

Leeks, cooked

124 g

1 leek

12

Lettuce, raw, shredded

36-47 g

1 cup

6-7

Mountain yam, cooked

145 g

1 cup

33

Mushrooms, cooked

156 g

1 cup

34

Mustard greens, cooked

150 g

1 cup

32

Okra, cooked

160 g

1 cup

32

Onions, cooked

210 g

1 cup

23

Parsley, fresh, chopped

60 g

1 cup

25

Pepper, sweet, raw, chopped

149 g

1 cup

9

Pumpkin, cooked, mashed

245 g

1 cup

20

Radicchio, raw

40 g

1 cup

3

Radishes, raw

116 g

1 cup

12

Seaweed, laver, raw

26 g

10 sheets

38

Spinach, raw

30 g

1 cup

16

Squash, summer, cooked

180 g

1 cup

23

Squash, winter, cooked

205 g

1 cup

23

Taro, cooked, sliced

132 g

1 cup

9

Tomatoes, fresh

149 g

1 cup

9

Tomato sauce

245 g

1 cup

17

Turnip greens, cooked

144 g

1 cup

37

Turnips, cooked, cubes

156 g

1 cup

14

Watercress, raw

34 g

1 cup

7

Yam, cooked

136 g

1 cup

27

Yardlong bean, cooked

104 g

1 cup

37

Zucchini, raw, chopped

124 g

1 cup

22

Brussels sprouts, cooked

155 g

1 cup

54

Hearts of palm, canned

146 g

1 cup

61

Potatoes, white + skin

148 g

1 med

56

Spinach, cooked

180 g

1 cup

99

Sweet potato, cooked

200 g

1 cup

74

Corn, sweet, cooked

165

1 cup

112

Peas, cooked

160 g

1 cup

130

Peas, raw

145 g

1 cup

119

Fruits

 

 

 

Apples, raw, sliced

125 g

1 cup

1

Apricots, dried

65 g

0.5 cup

10

Apricots, raw

155 g

1 cup

9

Bananas, raw, mashed

225 g

1 cup

18

Blueberries, raw

148 g

1 cup

18

Cherimoya, raw

160 g

1 cup

34

Cranberries, raw, chopped

110 g

1 cup

3

Dates

147 g

1 cup

32

Figs, raw

64 g

1 large (2.5″)

4

Gogi berries, dried

28 g

5 Tbsp

24

Grapefruit sections

230 g

1 cup

12-18

Grapes, fresh

92 g

1 cup

19

Guava, fresh

165 g

1 cup

26

Kiwi, raw, sliced

180 g

1 cup

43

Limes, raw

67 g

1 fruit

1

Mango, raw

165 g

1 cup

13

Melon, cantaloupe, raw

177 g

1 cup

21

Melon, honeydew, raw

170 g

1 cup

8

Nectarines, raw, sliced

143 g

1 cup

8

Olives, ripe, jumbo

15 g

1

2

Orange, raw, sections

180 g

1 cup

36

Papaya, raw

145 g

1 cup

3

Peach, raw

154 g

1 cup

15

Pear, Asian, raw

122 g

1 fruit

7

Pear, raw, slices

140 g

1 cup

3

Persimmons, raw

25 g

1 fruit

2

Pineapple, raw, chunks

165 g

1 cup

20

Plantains, raw, sliced

148 g

1 cup

25

Plums, raw, sliced

165 g

1 cup

13

Plums, dried

174 g

1 cup

28

Raisins, seedless

165 g

1 cup

35

Strawberries, raw

152 g

1 cup

3

Tangerines, raw, sections

195 g

1 cup

4

Watermelon, raw, balls

154 g

1 cup

9

Avocado, raw, cubes

150 g

1 cup

57

Figs, dried

149 g

1 cup

51

Jackfruit, raw

165 g

1 cup

56

Legumes

 

 

 

Black-eyed peas, cooked

165 g

1 cup

74

Hummus, homemade

60 g

1/4 cup

48

Miso

17 g

1 Tbsp

22

Okara

122 g

1 cup

50

Soy sauce (tamari)

18 g

1 Tbsp

30

Soy sauce (wheat and soy shoyu, low Na)

14 g

1 Tbsp

13

Soy milk, fortified

243 g

1 cup

39

Fava beans, cooked

170 g

1 cup

105

Lentils, sprouted, raw

77 g

1 cup

81

Lima beans, cooked

170 g

1 cup

116

Pigeon peas, red gram

168 g

1 cup

128

Soybeans, sprouted, cooked

94 g

1 cup

84

Tofu, soft

120 g

2.5 x 2.75 x 1″

101

Tofu, regular (medium firm)

124 g

0.5 cup

134

Tofu, firm (with calcium sulfate and nigari)

126 g

0.5 cup

139

Veggie sausages

50 g

2 links

126

Adzuki beans, cooked

230 g

1 cup

182

Chickpeas, cooked

164 g

1 cup

190

Cowpeas, cooked

171 g

1 cup

188

Kidney beans, cooked

177

1 cup

200

Lentils, cooked

198

1 cup

152

Lupins, cooked

166 g

1 cup

183

Mung beans, cooked

202 g

1 cup

170

Refried beans, canned reduced sodium

238 g

1 cup

155

Split peas, cooked

196 g

1 cup

167

Black turtle beans, cooked

185 g

1 cup

228

Black beans, cooked

172 g

1 cup

229

Cranberry beans, cooked

177 g

1 cup

248

Edamame, cooked

155 g

1 cup

215

Great Northern beans, cooked

177 g

1 cup

221

Navy beans, cooked

182 g

1 cup

201

Pink beans, cooked

169 g

1 cup

230

Small white beans, cooked

179 g

1 cup

242

Veggie burgers or soyburgers

70 g

1 patty

204

Tempeh

166 g

1 cup

290

Tofu, firm (prepared with calcium sulfate)

126 g

0.5 cup

266

White beans, cooked

179 g

1 cup

261

Soybeans, mature, cooked

172 g

 

385

Soy nuts, dry roasted

93 g

1 cup

497

Grains

 

 

 

Hominy, yellow

160 g

1 cup

50

Tapioca, uncooked

38 g

0.25 cup

1

Noodles, japanese, soba, cooked

114 g

1 cup

82

Barley. cooked

157

1 cup

68

Buckwheat groats, cooked

168 g

1 cup

74

Cornmeal

39 g

0.25 cup

64

Pasta, wheat, cooked

124 g

1 cup

79

Pasta, gluten-free, cooked, corn and quinoa

166 g

1 cup

98

Pasta, gluten-free, cooked, corn

140 g

1 cup

77

Sorghum grain, uncooked

48 g

0.25 cup

81

Triticale, uncooked

48 g

0.25 cup

98

Rice, white, long grain

158 g

1 cup

100

Amaranth, uncooked

48 g

0.25 cup

109

Millet, cooked

174 g

1 cup

122

Oats, uncooked

39 g

0.25 cup

122

Oat bran, cooked

219 g

1 cup

109

Pasta, gluten-free, cooked, brown rice

169 g

1 cup

134

Pasta, gluten-free, cooked, corn and rice

141 g

1 cup

102

Rice, brown, long grain

202 g

1 cup

117

Spelt, uncooked

44 g

0.25 cup

112

Wheat bran

58 g

1 cup

136

Wheat, hard, uncooked

48 g

0.25 cup

111

Wheat, sprouted

108 g

1 cup

125

Quinoa, cooked

185 g

1 cup

178

Kamut, cooked

172 g

1 cup

167

Wild rice, cooked

164 g

1 cup

195

Teff, uncooked

48 g

0.25 cup

207

Teff, cooked

252 g

1 cup

315

Nuts

 

 

 

Acorns, dried

28.35 g

1 ounce

39

Almonds

28.35 g

1 ounce

44

Almond butter

16 g

1 Tbsp

20

Cashew butter

16 g

1 Tbsp

50

Chestnuts, dried, European

28.35 g

1 ounce

33

Coconut, fresh, shredded

80 g

1 cup

50

Coconut, dried, shredded

28.35 g

1 ounce

37

Coconut water

240 g

1 cup

31

Macadamia nuts

28.35 g

1 ounce

7

Coconut milk, canned

240 g

1 cup

86

Hazelnuts

28.35 g

1 ounce

63

Pecans

28.35

1 ounce

54

Pine nuts

28.35 g

1 ounce

59

Peanuts, dry roasted

28.35 g

1 ounce

82

Walnuts, English

28.35 g

1 ounce

67

Cashews

28.35 g

1 ounce

103

Pistachio nuts

28.35 g

1 ounce

102

Brazil nuts

28.35 g

1 ounce

319

Seeds

 

 

 

Tahini (sesame seed butter), raw

15 g

1 Tbsp

88

Flaxseeds

28.35

1 ounce

105

Sunflower seeds

28.35 g

1 ounce

119

Chia seeds

28.35 g

1 ounce

167

Pumpkin seeds

28.35 g

1 ounce

171

Sesame seeds

28.35 g

1 ounce

159

Hempseeds (about 3 Tbsp)

28.35 g

1 ounce

264

Animal products

 

 

 

Eggs

33 g

1 large

132

Cheese, brie

28.35

1 ounce

168

Cheese, gouda

28.35

1 ounce

204

Milk, 1%

245 g

1 cup

215

Milk, 3.25%

244 g

1 cup

203

Yogurt, low fat, fruit

170

6 ounces

219

Cheese, parmesan, hard

28.35

1 ounce

272

Yogurt, plain, skim milk

170

6 ounces

287

Beef, lean, cooked

85 g

3 ounces

648

Chicken breast, cooked

85 g

3 ounces

675

Crab, cooked

134 g

1 leg

730

Fish, cod

85 g

3 ounces

448

Fish, salmon

85 g

3 ounces

640

Fish, tuna, canned

85 g

3 ounces

733

Ham, cooked

85 g

3 ounces

435

Lobster, cooked

145 g

1 cup

689

Pork, cooked

85 g

3 ounces

609

Shrimp, cooked

85 g

3 ounces

565

Turkey, roasted

85 g

3 ounces

670

 

NOTES:

  1. These figures in this table were sourced from the USDA National Nutrient Database for Standard Reference Release 28. http://ndb.nal.usda.gov/ndb/nutrients/index

 

  1. The chart is set up using food groups (e.g. vegetables, fruits, legumes, etc.). Within each group, you will notice a variety of colors which represent different categories of methionine concentration (see key that precedes the chart). Within each color category, foods appear in alphabetical order.

 

Selected References

Cavuoto P, Fenech MF. A review of methionine dependency and the role of methionine restriction in cancer growth control and life-span extension. Cancer Treat Rev. 2012 Oct;38(6):726-36.

Durando X, Thivat E, Gimbergues P, Cellarier E, Abrial C, Dib M, Tacca O, Chollet P. [Methionine dependency of cancer cells: a new therapeutic approach?].  Bull Cancer. 2008 Jan;95(1):69-76.

Hasek BE, Stewart LK, Henagan TM, Boudreau A, Lenard NR, Black C, Shin J, Huypens P, Malloy VL, Plaisance EP, Krajcik RA, Orentreich N, Gettys TW. Dietary  methionine restriction enhances metabolic flexibility and increases uncoupled respiration in both fed and fasted states. Am J Physiol Regul Integr Comp Physiol. 2010 Sep;299(3):R728-39.

Orgeron ML, Stone KP, Wanders D, Cortez CC, Van NT, Gettys TW. The impact of dietary methionine restriction on biomarkers of metabolic health. Prog Mol Biol Transl Sci. 2014;121:351-76.

Patil YN, Dille KN, Burk DH, Cortez CC, Gettys TW. Cellular and molecular remodeling of inguinal adipose tissue mitochondria by dietary methionine restriction. J Nutr Biochem. 2015 Nov;26(11):1235-47.

Plaisance EP, Greenway FL, Boudreau A, Hill KL, Johnson WD, Krajcik RA, Perrone CE, Orentreich N, Cefalu WT, Gettys TW. Dietary methionine restriction increases fat oxidation in obese adults with metabolic syndrome. J Clin Endocrinol Metab. 2011 May;96(5):E836-40.

Tapia-Rojas C, Lindsay CB, Montecinos-Oliva C, Arrazola MS, Retamales RM, Bunout D, Hirsch S, Inestrosa NC. Is L-methionine a trigger factor for Alzheimer’s-like neurodegeneration?: Changes in A? oligomers, tau phosphorylation, synaptic proteins, Wnt signaling and behavioral impairment in wild-type mice. Mol Neurodegener. 2015 Nov 21;10(1):62.

Trimmer EE. Methylenetetrahydrofolate reductase: biochemical characterization  and medical significance. Curr Pharm Des. 2013;19(14):2574-93.

Wanders D, Burk DH, Cortez CC, Van NT, Stone KP, Baker M, Mendoza T, Mynatt RL, Gettys TW. UCP1 is an essential mediator of the effects of methionine restriction on energy balance but not insulin sensitivity. FASEB J. 2015 Jun;29(6):2603-15.