|
Physiological factors (“physiological”: also know as “this is not a
disease”)
- Higher age
- Being male
- Menopause in
women
- High muscle
mass
|
|
Dietary factors
- Low intake of folate
(folic acid)
- Low intake of vitamin B12
- Low intake of vitamin B6
- Drinking coffee [This does not mean that drinking coffee is unhealthy.]
- Drinking alcohol [This does not mean that drinking alcohol in moderate amounts is unhealthy - although it may be.]
- Very high intake of the amino acid methionine [Ward et al. 2001]
- Low intake of omega-3 fatty acids (?)
|
|
Diseases or deficiencies
- Folate, vitamin B12, or vitamin B6 deficiency (Vitamin B12 deficiency is the one that is most relevant for vegans and vegetarians. A deficiency in folate or vitamin B6 does not usually occur in vegans. Vegans typically have a high intake of folate.)
- Renal impairment (i.e., impaired kidney function; kidney disease)
- Iodine deficiency (?) - high thyroid-stimulating hormone (TSH) levels are positively associated with plasma total homocysteine (tHcy) [Hvas & Nexo 2005: (r = 0.45; p = 0.02)]
- Hypothyroidism (which can be caused by iodine deficiency or iodine and selenium deficiency)
- Diabetes
- Psoriasis (an inflammatory skin disease)
- Malignancies (cancer)
|
|
Other lifestyle factors - Smoking cigarettes
- Lack of physical activity
|
|
Medications
- Lipid-lowering medications (namely: cholestyramine, nicotinic acid, fibric acid derivatives [e.g.,
fenofibrate]; NOT statins; “lipid-lowering” means cholesterol-lowering drugs)
- Anticonvulsants
(namely: phenytoin or carbamazepine; “anticonvulsants” are medications to
control seizures.)
- Sex hormones (androgens;
this means “testosterone supplements” also known as “steroid”, “anabolics”,
or “anabolic steroids”, the ones that some bodybuilders use.)
- Antirheumatic
drugs (namely: methotrexate)
- Some other
medications (namely: ciclosporin, diuretics, levodopa, methionine loading
medications [oral, intravenous, peritoneal], theophylline, trimethoprim)
|
|
Genetic factors (i.e. genetic predisposition; these are all problems with the functioning of some enzyme.) - Homozygosity for 5,10-Methylenetetrahydrofolate reductase C677T polymorphism (which causes decreased activity of this enzyme; this one is common.)
- Cystathionine gamma-lyase deficiency (This one is common.)
- Heterozygosity for cystathionine β synthase (CBS) deficiency (This one is uncommon.)
- Homocystinuria (caused by homozygous CBS deficiency) (This one is very rare.)
|
Based on:
Homocysteine (often abbreviated as "Hcy"):
Homocysteine is basically like the amino acid cysteine with an extra carbon atom (C), see cysteine below (the "chain" is one "corner" [= carbon atom] shorter):
