What is Methionine?

Summary

Optimal Intake (male 85kg/181cm / female 52kg/171cm)

Cognitive optimization male: 15-20 mg/kg/day (1,275-1,700 mg/day) with appropriate cofactors
Cognitive optimization female: 13-18 mg/kg/day (676-936 mg/day) with appropriate cofactors
Energy optimization male: 14-19 mg/kg/day (1,190-1,615 mg/day) for optimal performance
Energy optimization female: 12-17 mg/kg/day (624-884 mg/day) for optimal performance
Optimal methionine:glycine ratio: 1:2 to 1:3 for balanced health effects

Five best animal sources:

Beef liver: 85g (3 oz) provides 721 mg (14 mg/kg RDA reached with 5 oz)
Beef steak: 85g (3 oz) provides 660 mg (14 mg/kg RDA reached with 5.5 oz)
Wild salmon: 85g (3 oz) provides 626 mg (14 mg/kg RDA reached with 5.8 oz)
Pork: 85g (3 oz) provides 593 mg (14 mg/kg RDA reached with 6.1 oz)
Eggs: 2 large provide 534 mg (14 mg/kg RDA reached with 7 eggs)

Five best non-animal sources:

Brazil nuts: 28g (1 oz) provides 242 mg (14 mg/kg RDA reached with 4 oz)
Sesame seeds: 28g (1 oz) provides 154 mg (14 mg/kg RDA reached with 6.3 oz)
Spirulina: 28g (1 oz) provides 432 mg (14 mg/kg RDA reached with 2.3 oz)
Quinoa, cooked: 185g (1 cup) provides 191 mg (14 mg/kg RDA reached with 3.4 cups)
Soybeans, cooked: 172g (1 cup) provides 364 mg (14 mg/kg RDA reached with 1.6 cups)

Consistent intake required? Yes, methionine is an essential amino acid that cannot be synthesized by the body and must be consumed regularly. Daily intake is important for maintaining protein synthesis, methylation processes, and antioxidant production. However, excessive intake over prolonged periods may have negative effects, suggesting balanced consumption is optimal.

Are higher doses dangerous? Unlike some nutrients, methionine does not have an established upper limit. However, chronic high methionine intake without adequate glycine balance may promote increased homocysteine levels, oxidative stress, and potentially accelerated aging processes. The key is maintaining balance with other amino acids, particularly glycine, and ensuring adequate B-vitamins for proper metabolism.

Optimal timing for intake:

With complete meals: Consume methionine as part of complete protein sources with complementary amino acids
Morning/post-workout: For protein synthesis support and muscle recovery
With B-vitamins: Ensure adequate B6, B9 (folate), and B12 for proper methionine metabolism
Balance with glycine: Include glycine-rich foods or supplements to maintain optimal amino acid balance
Cyclic approach: Some research suggests benefits to occasional lower-methionine days for metabolic flexibility

Introduction

Methionine is one of the nine essential amino acids that must be obtained through diet, as the human body cannot synthesize it. This sulfur-containing amino acid plays numerous critical roles:

Protein synthesis (particularly as a starter amino acid initiating protein translation)
Methylation reactions via S-adenosylmethionine (SAM)
Antioxidant production through the transsulfuration pathway
Lipid metabolism and transport
Polyamine synthesis for cell growth and differentiation
Detoxification processes
Heavy metal chelation and removal
Cartilage formation
Immune system support

Methionine is unique among amino acids due to its prominent role in methylation, a fundamental biochemical process that regulates gene expression, neurotransmitter production, detoxification, energy metabolism, and many other vital functions. It serves as the precursor to S-adenosylmethionine (SAM), often called the universal methyl donor.

Despite its essential roles, methionine has a complex relationship with health and longevity. While adequate intake is crucial for cognitive function, physical performance, and overall health, excessive consumption without proper balance may contribute to certain health issues. Research into methionine restriction has shown potential benefits for metabolic health and longevity in animal models, highlighting the importance of optimal rather than maximal intake.

According to Dr. Paul Saladino and other health experts focusing on evolutionary approaches to nutrition, methionine intake should be considered in balance with glycine and other nutrients, rather than in isolation. Dr. Rhonda Patrick emphasizes its critical role in methylation pathways, while Dr. Andrew Huberman notes its importance for cognitive function and neurological health when properly metabolized.

Effects at Different Methionine Levels

Optimal Levels

Efficient protein synthesis and tissue repair
Balanced methylation reactions throughout the body
Healthy neurotransmitter production and recycling
Adequate antioxidant production (glutathione)
Proper detoxification capacity
Optimal immune function
Healthy cognitive performance
Effective energy metabolism
Balanced lipid metabolism
Normal homocysteine levels
Proper DNA/RNA synthesis and repair
Effective stress response and resilience
Healthy hair, skin, and nail growth

Deficiency

Impaired protein synthesis
Reduced growth in children
Hair, skin, and nail problems
Weakened immune function
Diminished cognitive performance
Mood disturbances
Reduced detoxification capacity
Fatigue and weakness
Impaired wound healing
Decreased stress resilience
Reduced collagen production
Compromised liver function
Altered fat metabolism

Severe Deficiency

Growth failure in children
Severe muscle wasting
Fatty liver development
Compromised immunity and increased infection risk
Significant mental and physical fatigue
Profound metabolic disruptions
Serious neurological symptoms
Impaired methylation affecting multiple systems
Major disruptions to hormone balance
Compromised cardiovascular function
In extreme cases, organ dysfunction

Excess (Chronic High Intake)

Elevated homocysteine levels
Increased oxidative stress
Potentially accelerated aging processes
Possible methylation dysregulation
Increased inflammation markers
Potential imbalance in amino acid transport and utilization
Possible contribution to certain metabolic disorders
Increased demand for B-vitamins
Potential negative effects on longevity pathways
Disturbed gut microbiome balance
Increased cellular burden for detoxification

Recommended Dosage

Methionine intake is measured in milligrams (mg) and often expressed in terms of mg per kilogram of body weight.

General Recommendations

By Age Group

Age Group	RDA (mg/kg/day)
Infants (0-6 months)	25 (AI)
Infants (7-12 months)	22
Children (1-3 years)	19
Children (4-8 years)	19
Children (9-13 years)	19
Adolescents (14-18 years)	15
Adults (19+ years)	14
Pregnancy	16
Lactation	17

*Note: These recommendations are for total sulfur amino acids (methionine + cysteine), as cysteine can spare some methionine requirements. Typically, at least 40-70% should come from methionine.

For Specific Body Types

Male (85kg, 181cm)

Standard RDA: 1,190 mg/day (14 mg/kg/day × 85 kg)
Adjusted for athletic activity: 1,275-1,445 mg/day (15-17 mg/kg/day)
For optimal cognitive performance (Saladino/Patrick): 1,275-1,700 mg/day (15-20 mg/kg/day) with balanced glycine intake

Female (52kg, 171cm)

Standard RDA: 728 mg/day (14 mg/kg/day × 52 kg)
Adjusted for athletic activity: 780-884 mg/day (15-17 mg/kg/day)
For optimal cognitive performance (Saladino/Patrick): 676-936 mg/day (13-18 mg/kg/day) with balanced glycine intake

The RDA represents the minimum amount needed to prevent deficiency in a healthy individual. Many nutrition experts suggest optimal intake may be higher for physically active individuals but should be balanced with glycine and supported by adequate B-vitamins to ensure proper metabolism.

According to Dr. Paul Saladino and other evolutionary health researchers, the methionine:glycine ratio may be more important than absolute methionine intake, with an optimal ratio of approximately 1:2 to 1:3 for balanced health effects.

Safe Upper Limits & Toxicity

Maximum Safe Dosage

Upper Intake Levels

There is no established Upper Limit (UL) for methionine by major health organizations. However, caution is advised with very high intakes.

For Specific Body Types

Male (85kg, 181cm)

No established Upper Limit
Research suggests caution with chronic intakes above 3-4 times the RDA
Higher intakes should be balanced with proportional glycine

Female (52kg, 171cm)

No established Upper Limit
Similar caution advised with very high intakes
Balanced amino acid intake is more critical than absolute methionine levels

Note: While acute toxicity from food sources is extremely unlikely, chronically elevated methionine intake may contribute to increased homocysteine levels and oxidative stress when not properly balanced with other nutrients, particularly glycine and B-vitamins.

Dr. Rhonda Patrick and other researchers highlight that the context of methionine intake matters significantly—consumption as part of whole protein foods with natural amino acid balances poses different effects than isolated supplementation.

Dangerous Dose Levels

Acute Toxicity: Extremely rare from food sources; would require massive supplementation
Chronic Concerns: More related to imbalances than absolute intake; chronically high methionine without sufficient glycine and B-vitamins may have adverse effects
Methionine Loading: Used in clinical testing (100 mg/kg dose) to assess homocysteine metabolism

Signs of Methionine Excess

Symptoms of chronic methionine imbalance may include:

Elevated homocysteine levels
Increased oxidative stress markers
B-vitamin depletion
Alterations in lipid metabolism
Increased inflammatory markers
Changes in methylation patterns
Possible acceleration of certain aging processes

Health Effects and Benefits

Protein Synthesis and Tissue Repair

Initiating amino acid for protein translation
Critical component of structural and functional proteins
Essential for wound healing and tissue regeneration
Supports maintenance of muscle mass
Required for collagen production
Enables growth in children and adolescents
Facilitates recovery from injury or exercise
Maintains healthy skin, hair, and nail structure

Methylation Support

Precursor to S-adenosylmethionine (SAM), the universal methyl donor
Enables DNA and RNA methylation for gene regulation
Supports neurotransmitter synthesis and metabolism
Essential for creatine production
Facilitates phospholipid synthesis for cell membranes
Enables hormone metabolism and regulation
Supports carnitine synthesis for fat metabolism
Enables epigenetic adaptations to environment and lifestyle

Antioxidant Production

Precursor to cysteine and glutathione (master antioxidant)
Supports cellular defense against oxidative damage
Enables detoxification of environmental toxins
Helps neutralize reactive oxygen species
Protects cellular proteins and DNA from damage
Supports immune cell function
Contributes to cellular longevity
Helps maintain mitochondrial integrity

Neurological Function

Critical for neurotransmitter production and regulation
Supports myelin sheath integrity
Enables cognitive performance and memory
Facilitates neuroplasticity processes
Supports healthy mood regulation
Provides sulfur for brain biochemistry
Helps maintain blood-brain barrier integrity
Supports energy metabolism in neural tissues

Liver Health and Detoxification

Essential for phase II detoxification pathways
Supports bile production and secretion
Enables processing of fat-soluble toxins
Helps prevent fatty liver development
Supports liver protein synthesis
Contributes to glycogen metabolism
Assists in ammonia neutralization
Supports overall metabolic health

Immune System Support

Required for antibody production
Supports white blood cell function
Enhances natural killer cell activity
Facilitates cytokine production and regulation
Enables proper immune signaling
Supports mucosal barrier maintenance
Contributes to immune cell proliferation
Helps regulate inflammation processes

Deficiency Symptoms

Methionine deficiency can cause:

Edema (fluid retention)
Skin lesions and poor wound healing
Hair loss or changes in hair texture
Digestive issues
Fatty liver development
Growth retardation in children
Muscle weakness and loss
Impaired immune function
Mood disturbances and irritability
Cognitive impairment
Fatigue and weakness
Anemia (in severe cases)
Compromised detoxification ability
Increased susceptibility to environmental toxins
Poor protein synthesis and tissue repair
Reduced stress resilience
Hormonal imbalances
Nail brittleness or abnormalities

Sources of Methionine

Food Sources with Amounts to Meet Requirements

Animal Sources

Food	Serving Size	Methionine Content (mg)	Amount to Reach RDA (1,190 mg for 85kg male)	Amount to Reach UL (N/A)
Beef liver	85g (3 oz)	721	140g (5 oz)	N/A
Beef steak	85g (3 oz)	660	153g (5.5 oz)	N/A
Wild salmon	85g (3 oz)	626	162g (5.8 oz)	N/A
Pork	85g (3 oz)	593	171g (6.1 oz)	N/A
Eggs	2 large	534	4.5 eggs	N/A
Chicken breast	85g (3 oz)	558	182g (6.5 oz)	N/A
Turkey	85g (3 oz)	582	174g (6.2 oz)	N/A
Lamb	85g (3 oz)	569	178g (6.3 oz)	N/A
Tuna	85g (3 oz)	603	168g (6 oz)	N/A
Cheese, parmesan	28g (1 oz)	233	143g (5.1 oz)	N/A

Plant Sources

Food	Serving Size	Methionine Content (mg)	Amount to Reach RDA (1,190 mg for 85kg male)	Amount to Reach UL (N/A)
Brazil nuts	28g (1 oz)	242	138g (4.9 oz)	N/A
Sesame seeds	28g (1 oz)	154	217g (7.7 oz)	N/A
Spirulina	28g (1 oz)	432	77g (2.8 oz)	N/A
Quinoa, cooked	185g (1 cup)	191	1,154g (6.2 cups)	N/A
Soybeans, cooked	172g (1 cup)	364	562g (3.3 cups)	N/A
Hemp seeds	28g (1 oz)	194	172g (6.1 oz)	N/A
Chia seeds	28g (1 oz)	115	290g (10.4 oz)	N/A
Rice, brown	195g (1 cup)	121	1,920g (9.8 cups)	N/A
Oats, raw	81g (1 cup)	235	410g (5.1 cups)	N/A
Beans, black	172g (1 cup)	150	1,360g (7.9 cups)	N/A

*Note: Methionine content can vary based on growing conditions, preparation methods, and specific varieties. These values are averages. There is no established UL (Upper Limit) for methionine from food sources.

Supplements

Types of Methionine Supplements

L-Methionine: The biologically active form used in most supplements
N-Acetyl-L-Methionine: May have enhanced absorption characteristics
S-Adenosyl Methionine (SAMe): Direct methyl donor derivative of methionine, often used for mood, liver, and joint support
Methionine Hydroxy Analog (MHA): Used primarily in animal nutrition
Liposomal Methionine: Enhanced bioavailability through liposomal delivery
Methyl Donors: Combination supplements that include methionine with other methylation supporters like B-vitamins

Considerations When Choosing Supplements

Necessity: Most individuals consuming adequate protein receive sufficient methionine without supplementation
Form: L-methionine is the standard, while SAMe is a specialized support for specific conditions
Complementary Nutrients: Should include B6, B9, B12, and glycine to ensure proper metabolism
Quality: Select brands with third-party testing (USP, NSF, ConsumerLab)
Dosage: Start with lower doses (250-500mg) if supplementing
Timing: Taking with meals that contain complementary nutrients improves utilization
Balance: Consider maintaining methionine:glycine ratio if supplementing
Medical Supervision: Recommended for any ongoing methionine supplementation

Dr. Paul Saladino and many other health experts generally recommend obtaining methionine from whole food sources rather than isolated supplements, particularly emphasizing nutrient-dense animal products that contain natural balances of amino acids.

Methionine Optimization Strategies

Metabolic Enhancement

B-Vitamin Adequacy: Ensure sufficient B6, folate, and B12 for proper methionine metabolism
Glycine Balance: Maintain adequate glycine intake (2-3x methionine intake) through collagen, bone broth, or glycine supplements
Choline Support: Include choline-rich foods (eggs, liver) to support methyl group metabolism
Zinc Adequacy: Ensure optimal zinc status to support enzymatic processes involving methionine
Magnesium Optimization: Maintain adequate magnesium for proper enzymatic reactions
Sulfur Donors: Include other sulfur-containing foods (garlic, onions, cruciferous vegetables) to support overall sulfur metabolism
Methylation Support: Consider periodic targeted support with trimethylglycine (TMG) or MSM if indicated
Stress Management: Reduce stress-related methyl group depletion through stress management practices

Dietary Strategies

Nose-to-Tail Eating: As advocated by Dr. Saladino, consuming a variety of animal parts naturally balances methionine and glycine
Protein Cycling: Strategically varying protein intake to optimize anabolic and longevity pathways
Bone Broth Integration: Regular consumption provides glycine to balance methionine
Animal Protein Balance: Include both muscle meats (higher methionine) and collagenous tissues (higher glycine)
Seafood Inclusion: Regular consumption of seafood provides balanced amino acid profiles
Organ Meat Rotation: Include various organ meats for complete amino acid profiles and cofactors
Balanced Plant Proteins: If consuming plant proteins, combine different sources for amino acid complementarity
Ancestral Approach: Consider traditional eating patterns that naturally balanced amino acids through whole-animal consumption

Supplement Strategies for Optimal Energy

Targeted SAMe: Consider SAMe supplementation for specific methylation support rather than isolated methionine
Methylation Support: B-complex vitamins with methylated forms (methylfolate, methylcobalamin)
Complementary Cofactors: Include trimethylglycine, choline, or betaine to support methionine metabolism
Cycling Approach: Some practitioners recommend periodic methylation support rather than continuous supplementation
Testing-Based Approach: Use functional testing (homocysteine, methylation panels) to guide precise supplementation
Pre/Post Workout: Time protein intake containing balanced amino acids around exercise
Glycine Complementation: Supplement glycine (3-5g) when consuming high-methionine meals
Circadian Alignment: Coordinate protein intake with natural circadian methylation patterns

Synergistic Nutrients

Vitamin B6: Critical for transsulfuration pathway converting homocysteine to cysteine
Folate (B9): Essential for recycling homocysteine back to methionine
Vitamin B12: Required for methionine synthase function in homocysteine remethylation
Glycine: Balances methionine metabolism and supports glutathione production
Choline: Provides methyl groups that spare methionine requirements
Betaine: Alternative methyl donor that supports methionine conservation
Vitamin B2: Cofactor for methylation enzymes
Magnesium: Required cofactor for numerous enzymes in methionine metabolism
Zinc: Supports enzymatic reactions involving sulfur amino acids
Selenium: Works with methionine in antioxidant systems

Special Considerations

Pregnancy and Breastfeeding

Methionine needs increase during pregnancy
Critical for fetal development, particularly neural tube formation
Important for preventing certain birth defects
Supports maternal liver function during increased metabolic demands
Enhanced requirement during breastfeeding for milk protein production
RDA increases to 16-17 mg/kg/day during pregnancy and lactation
Balanced intake with other amino acids remains important
Should be obtained primarily from whole food protein sources

Medical Conditions Affecting Methionine

Homocystinuria: Genetic disorder affecting methionine metabolism
Liver disease: Can impair methionine metabolism
Kidney disease: May affect amino acid clearance and balance
Methylation disorders: Genetic variations affecting methionine utilization
Inflammatory conditions: May increase methionine requirements
Cardiovascular disease: Monitoring homocysteine advisable with methionine intake
Certain cancers: May alter methionine metabolism and requirements
Parkinson’s disease: May benefit from balanced SAMe support

Medication Interactions

Levodopa: Methionine may interact with Parkinson’s medications
Antidepressants: SAMe may interact with certain antidepressants
Anticoagulants: Theoretical interaction with methionine metabolism
Methotrexate: Depletes folate needed for methionine metabolism
Nitrous oxide: Inactivates B12, affecting methionine synthase
Antacids: May reduce absorption of protein-bound methionine
Anti-seizure medications: May affect methionine metabolism
Hormonal contraceptives: May alter B-vitamin status affecting methionine pathways

Personalized Recommendations

For Male (85kg, 181cm)

Aim for approximately 1,190-1,700 mg methionine daily (14-20 mg/kg/day)
Ensure this comes primarily from quality whole food protein sources
Include 2-3 servings of methionine-rich foods daily (eggs, meat, fish)
Balance with glycine-rich foods (bone broth, collagen, skin, tendons) at a 1:2 or 1:3 ratio
Support with adequate B-vitamins through nutrient-dense foods (liver, eggs, seafood)
Consider periodic methionine “cycling” with lower-methionine days
Include sulfur-rich vegetables regularly (garlic, onions, cruciferous vegetables)
Stay well-hydrated to support amino acid metabolism
For cognitive enhancement, ensure adequate choline alongside methionine
For physical performance, time higher methionine meals around workouts
Monitor homocysteine levels annually if consistently consuming high-protein diet
Adjust based on energy levels, performance metrics, and cognitive function

For Female (52kg, 171cm)

Target approximately 728-936 mg methionine daily (14-18 mg/kg/day)
Prioritize high-quality animal proteins for complete amino acid profiles
Include at least 2 servings of methionine-containing foods daily
Balance with glycine-rich foods at a similar 1:2 or 1:3 ratio
Pay particular attention to B-vitamin status, especially during menstruation
Consider additional methylation support during certain phases of menstrual cycle
Include choline-rich foods (eggs, liver) regularly for cognitive support
Be mindful that oral contraceptives may affect B-vitamin status and methionine metabolism
Monitor energy levels and adjust protein timing to optimize metabolism
Support liver function through cruciferous vegetables and adequate hydration
Consider periodic testing of methylation markers if experiencing energy or cognitive issues
Adjust based on performance, recovery, and cognitive metrics

Activity-Level Adjustments

Sedentary: Standard RDA is usually sufficient (14 mg/kg/day)
Moderately Active: Increase to 15-16 mg/kg/day
Athletic/Intense Training: Consider 16-18 mg/kg/day
Strength Training Focus: Emphasize post-workout methionine-rich meals
Endurance Athletes: May benefit from strategic methionine timing around training
Recovery Phases: Emphasize balanced methionine:glycine ratio
Cognitive Demands: Ensure choline and methionine sufficiency during mentally demanding periods

Methionine for Cognitive Performance

Current Research Highlights

Methionine via SAMe production directly impacts neurotransmitter synthesis
Adequate methionine supports memory formation and recall
Essential for maintaining myelin sheath integrity in neural pathways
Supports dopamine, serotonin, and norepinephrine production and metabolism
Enables neuroplasticity through methylation-dependent processes
Contributes to phospholipid synthesis for neural cell membranes
Supports neuroprotective mechanisms through glutathione production
May help regulate neuroinflammatory processes

Implementation Strategies

Ensure balanced methionine intake with complementary nutrients rather than excess
Combine with choline sources (eggs, liver) for synergistic cognitive benefits
Include B-vitamin cofactors, particularly B6, folate, and B12
Time protein-rich meals to support cognitive demands
Balance with glycine to prevent potential downsides of isolated high methionine
Monitor subjective cognitive effects when adjusting protein intake
Consider periodic SAMe supplementation for targeted cognitive support
Pair with omega-3 fatty acids for synergistic neural benefits
Support detoxification pathways to ensure optimal brain function

Methionine for Energy Production

Metabolic Mechanisms

Critical for creatine synthesis, a rapid energy substrate for high-intensity activities
Supports mitochondrial function and integrity
Essential for carnitine production, facilitating fatty acid transport for energy
Enables ATP production through various metabolic pathways
Supports insulin sensitivity when properly balanced
Helps regulate cellular energy homeostasis
Contributes to metabolic flexibility (switching between energy substrates)
Supports thyroid hormone metabolism affecting basal metabolic rate

Implementation Strategies

Consume sufficient but not excessive methionine for optimal energy metabolism
Balance with glycine to support mitochondrial health
Include supporting B-vitamins with methionine-rich foods
Time higher protein meals strategically around energy demands
Support methylation pathways for efficient energy metabolism
Consider creatine supplementation alongside balanced methionine intake
Ensure adequate hydration for optimal amino acid utilization
Monitor energy levels when adjusting protein quantity and quality

Expert Insights

Dr. Paul Saladino emphasizes the importance of nose-to-tail eating for balanced methionine:glycine ratios
Dr. Rhonda Patrick highlights methionine’s critical role in methylation and its impact on energy metabolism
Dr. Andrew Huberman notes the connection between proper methionine metabolism and cognitive energy
Research suggests that balanced methionine intake—neither too high nor too low—may be optimal for long-term cellular energy production
Emerging research connects methionine metabolism to mitochondrial health and function

Summary

Methionine is an essential sulfur-containing amino acid that plays crucial roles in protein synthesis, methylation processes, antioxidant production, and numerous metabolic pathways. Its proper intake and metabolism are essential for cognitive function, energy production, detoxification, and overall health.

Getting Enough: Most people consuming adequate protein (especially animal foods) receive sufficient methionine
Avoiding Excess: While no official upper limit exists, balanced intake with glycine (1:2-3 ratio) appears optimal for long-term health
Best Approach: Focus on whole food sources with natural amino acid profiles rather than isolated supplementation
Methylation Support: Ensure adequate B-vitamins, choline, and other cofactors for proper methionine metabolism
Energy Optimization: Maintain appropriate methionine intake with supporting nutrients for mitochondrial function
Cognitive Enhancement: Support balanced methionine metabolism for neurotransmitter production and neural health
Synergistic Approach: Consider methionine in the context of overall protein quality, B-vitamin status, and glycine balance

Remember that individual nutritional needs vary based on activity level, stress, metabolic health, genetic factors, and life stage. A “food first” approach focusing on nutrient-dense animal proteins, balanced with glycine-rich foods and supported by adequate cofactors, provides the foundation for optimal methionine metabolism.