Folates are normally found in a wide variety of foods and are commonly consumed through a diet of green leafy vegetables, sprouts, fruits, brewer's yeast, and animal products such as milk and dairy products, egg yolk and liver.
Unfortunately folates contained in foods are unstable and susceptible to oxidation; they rapidly lose activity during food processing, manufacturing and storage and have a bioavailability range of 25-50%, depending on the kind of food. Fresh leafy vegetables stored at room temperature may lose up to 70% of their folate activity within three days and a cooking process in water can increase the loss to 95%.
Humans cannot synthesize folate and because of its water soluble nature, the body stores folate to a limited extent. For this reason folate represents a dietary requirement and must be consumed by diet. Whether we ingest food containing natural or synthetically-derived folates, they are metabolized to 5-methyltetrahydrofolate, which is considered the biologically active form of the B-vitamin folic acid.
Folate deficiency represents one of the most common nutritional deficiencies and may occur when dietary intake is inadequate, when an increased need is not matched by an increased intake (particular physiological conditions such as pregnancy, lactation, child growth), when there is altered absorption/excretion (or losses) and when metabolism or drug use interferes with the ability of the body to use folate.
Several conditions can lead to nutritional folate deficiency such as enzyme defects, malabsorption, digestive system pathology, liver disease but also conditions with a high rate of cell turnover such as rapid tissue growth (infants, kids and adolescents) pregnancy and lactation.
In severe cases deficiency can cause many clinical abnormalities, including macrocytic anemia, cardiovascular diseases, birth neural tube defects (NTDs) and carcinogenesis. Folate deficiency is associated with elevated levels of homocysteine, cerebrovascular and neurological diseases, and mood disorders.
Deficiency of folate may be asymptomatic or present with symptoms of anemia, diarrhea, loss of appetite, and weight loss. Additional signs are weakness, sore tongue, headaches, heart palpitations, irritability, and behavioral disorders.
• Neural-tube defect
• Male and female infertility
• Spontaneous abortion
• Coronary heart disease
• Macrocytic anaemia
• Methotrexate therapy
• Irritable bowel disease
• Cognitive deficits in elderly
• Lifestyle putting people at risk of low folate levels: