Effect of Folic Acid on the Body

Folic acid, also known as vitamin B9 or folate in its natural form, is an essential nutrient that plays a fundamental role in the functioning of the human body. It is a water-soluble vitamin that the body cannot store in large quantities, so it must be obtained regularly through diet or supplements. Its main action lies in the synthesis and repair of DNA, the genetic material that directs cell growth and division. This makes it a key component for the formation of red blood cells, preventing anemia, and for the proper development of tissues during critical stages such as pregnancy. In the bloodstream, folic acid is converted into active forms that help metabolize amino acids and regulate homocysteine levels, a compound that, in excess, can damage arteries and increase cardiovascular risks. Its absorption occurs primarily in the intestines, and excess is eliminated by the kidneys through urine, minimizing toxic accumulations when consumed in moderate doses.

In the body, folic acid acts as a cofactor in numerous biochemical reactions. For example, it works with other B vitamins, such as B6 and B12, to convert homocysteine into methionine, an essential amino acid for the production of proteins and other vital compounds. This conversion not only maintains the chemical balance in the blood but also supports the integrity of the nervous system and the production of neurotransmitters. In rapidly dividing cells, such as those in the bone marrow or intestinal lining, folate ensures that DNA replicates properly, preventing mutations that could lead to long-term health problems. During pregnancy, its role is even more critical, as it contributes to the closure of the fetal neural tube in the first weeks of gestation, a process that occurs before many women even know they are pregnant. Without sufficient folic acid, this development can fail, resulting in serious birth defects such as spina bifida or anencephaly.

The effects of folic acid extend beyond basic prevention, influencing the body's overall health. By promoting the formation of healthy red blood cells, it combats megaloblastic anemia, a condition in which blood cells are abnormally large and ineffective, causing fatigue, weakness, and pallor. In the cardiovascular field, by reducing homocysteine levels, it can mitigate arterial inflammation and clot formation, potentially reducing the risk of heart attacks and strokes. Studies have shown that in people with hypertension, an adequate intake of folic acid can significantly reduce the incidence of strokes—around 21% in some cases. Furthermore, its indirect antioxidant action helps neutralize free radicals, protecting cells from oxidative damage that accelerates aging and chronic diseases.

Turning to specific benefits, folic acid stands out for its ability to prevent neural tube defects in newborns, a benefit supported by decades of research and public health recommendations. For women of childbearing age, consuming sufficient amounts before and during pregnancy not only reduces these risks by up to 70% but may also decrease the likelihood of premature birth, congenital heart defects, and other fetal problems. Some preliminary studies suggest possible protection against autism spectrum disorder, although more evidence is needed to confirm this. In adults, benefits include improved mental health, as folate supports the production of serotonin and dopamine, key neurotransmitters for mood. In combination with antidepressants, it may enhance their effectiveness in people with folate deficiency, alleviating symptoms of resistant depression. Another notable benefit is its role in cancer prevention, particularly when obtained from natural sources such as leafy green vegetables; however, high-dose supplements may have mixed effects in this regard.

In terms of cardiovascular health, folic acid offers protection by lowering elevated homocysteine, an independent risk factor for heart and blood vessel disease. Research indicates that adequate daily intake can reduce the risk of stroke by 10% and heart disease by 4%, especially in populations with common nutritional deficiencies. For people exposed to toxins such as arsenic, present in some contaminated water, folate helps eliminate it from the body, reducing potential damage to the skin, lungs, and bladder. In the context of anemia, its benefits are immediate: by correcting the deficiency, symptoms such as fatigue and lack of concentration improve rapidly, often within days. Furthermore, in aging, it may help maintain cognitive function, although there is no conclusive evidence that it prevents dementia or Alzheimer's.

The benefits extend to the digestive and bone systems, where folic acid supports intestinal cell regeneration and nutrient absorption, preventing problems such as chronic diarrhea or malabsorption. In postmenopausal women, combined with other nutrients, it may help maintain bone density, although this requires further study. For athletes or people with high physical demands, folate ensures adequate oxygenation through efficient red blood cells, improving performance and recovery. In general, an optimal intake of folic acid promotes healthy aging by reducing systemic inflammation and supporting immunity, as immune cells depend on rapid cell division.

Regarding dosages, recommendations vary by age, sex, and life circumstances. For adults in general, a daily intake of 400 micrograms of dietary folate equivalents is suggested, considering the better absorption of synthetic folic acid compared to natural folic acid. In children, doses are lower: 65 micrograms for infants 0 to 6 months, gradually increasing to 300 micrograms for adolescents 9 to 13 years of age. During pregnancy, the need increases to 600 micrograms to support rapid fetal growth, and during lactation, to 500 micrograms. All women of reproductive age, even if not planning pregnancy, should consume at least 400 micrograms of folic acid daily from supplements or fortified foods, in addition to dietary folate, to cover potential deficiencies. In cases of diagnosed deficiency, such as anemia or malabsorption, physicians may prescribe therapeutic doses of up to 1,000 micrograms, but always under supervision.

The method of administration influences the effective dose. Folic acid is found in multivitamins, fortified cereals, breads, and pastas, where 1 microgram of folic acid is equivalent to 1.7 micrograms of natural folate due to its greater bioavailability. For people with genetic mutations such as MTHFR C677T, which affect folate metabolism, it is recommended to adhere to standard doses of folic acid, not alternative forms such as 5-MTHF, to prevent neural defects. It is important not to exceed the upper limits: 1,000 micrograms daily for adults, and less for children, to avoid complications. The dose is usually taken once a day, with or without food, and if missed, it should be taken as soon as possible without doubling up.

Although folic acid is generally safe, it can cause side effects, especially at high doses. Common are gastrointestinal discomfort such as nausea, bloating, gas, and loss of appetite, which are usually mild and transient. Some people report a bad taste in the mouth, irritability, confusion, or sleep disturbances. Rare allergic reactions include rash, itching, redness, or difficulty breathing, requiring immediate medical attention. A worrisome effect is that high doses can mask a vitamin B12 deficiency, correcting anemia but allowing neurological damage to progress, which could cause irreversible problems such as numbness, weakness, or dementia.

Regarding cancer, while dietary folate is protective, excessive supplementation may increase the risk of colorectal adenomas or colorectal cancer in predisposed individuals, according to observational studies. High concentrations of unmetabolized folic acid in the blood have not shown confirmed harm, but are being monitored for possible impacts on cellular health. In children, side effects are rare, but accidental overdoses can cause symptoms similar to those in adults. These effects generally disappear with dose adjustment, but persistent ones require medical consultation.

To avoid complications, strict precautions should be taken. First, obtain folate preferably from natural sources such as spinach, broccoli, legumes, citrus fruits, and nuts, supplementing only when necessary, such as during pregnancy or due to poor diets. Always consult a healthcare professional before starting supplements, especially if taking medications such as anticonvulsants (phenytoin, carbamazepine), methotrexate for cancer or arthritis, or sulfasalazine for colitis, as folic acid may reduce their effectiveness or interact negatively. People with a history of cancer should avoid high doses without supervision, given the possible risk of promoting existing tumors.

Other precautions include monitoring for concurrent deficiencies, such as B12, through regular blood tests, especially in strict vegetarians or the elderly. Store supplements in a cool, dry place, out of reach of children, and in case of overdose, contact poison control immediately. During pregnancy, begin supplementation at least one month before conceiving and continue until the third month. Avoid excessive alcohol, which interferes with folate absorption, and in cases of abuse, seek medical help to adjust the dose. Finally, avoid sharing supplements and attend checkups to assess your response, ensuring that the benefits outweigh any potential risks.

In short, folic acid is an invaluable ally for health, but its use must be balanced and informed. Following these guidelines will maximize its positive effects while minimizing complications, contributing to overall well-being throughout life.