Folate, also known as vitamin B9, is a B vitamin that plays a role in numerous bodily functions. It is involved in processes like DNA synthesis, repair, and cell division, making it particularly important for the production of red blood cells and for proper development during pregnancy. While adequate folate levels are beneficial, an excess can also raise concerns, prompting a closer look at what high levels might mean for your health.
What Elevated Folate Means
Folate encompasses various forms of vitamin B9, including the naturally occurring form found in foods and synthetic folic acid, which is commonly added to supplements and fortified foods. Naturally occurring folate is present in foods such as leafy green vegetables, citrus fruits, and legumes. Folic acid, a more stable man-made form, is frequently used to fortify products like cereals, bread, and pasta.
Elevated folate levels are identified through blood tests, which measure either serum folate or red blood cell (RBC) folate. Normal serum folate levels for adults range from 3–10 ng/mL. RBC folate levels, which reflect longer-term folate status, are between 140–630 ng/mL. A serum folate level greater than 20 ng/mL is considered elevated.
Reasons for High Folate
A common reason for elevated folate levels is consuming excessive amounts through dietary supplements, particularly those containing high doses of folic acid. Many over-the-counter vitamins and prescription medications contain folic acid. While beneficial for deficiencies or during pregnancy, excessive intake can lead to high levels. For instance, taking more than 800 micrograms (µg) of folic acid daily is a common cause.
Regular consumption of foods fortified with folic acid also contributes to higher folate levels. These foods, such as breakfast cereals, bread, and pasta, are fortified with folic acid to enhance nutritional intake. This widespread fortification means many individuals consume significant amounts of synthetic folate through their daily diet.
Genetic variations can influence how the body processes folate, leading to its accumulation. For example, polymorphisms in the MTHFR gene can affect the enzyme responsible for converting folic acid into its active form. While individuals with these variants can still process folate, the efficiency of this conversion can be reduced, contributing to higher levels of unmetabolized folic acid in the bloodstream.
Certain medical conditions can also impact folate metabolism or excretion, leading to elevated levels. Liver diseases, like cirrhosis, can disrupt the liver’s role in processing and storing folate, causing it to build up in the bloodstream. Kidney disease can also result in increased circulating folate concentrations due to reduced excretion. Additionally, pernicious anemia, an autoimmune condition that impairs vitamin B12 absorption, may present with high folate levels, as the body’s inability to utilize folate properly in the absence of sufficient B12 can lead to its accumulation.
Impact on Health
A primary concern regarding high folate levels is their ability to mask a vitamin B12 deficiency. Both folate and vitamin B12 are involved in red blood cell production, and a deficiency in either can lead to megaloblastic anemia. High folic acid intake can alleviate the anemia caused by a B12 deficiency, allowing neurological damage to progress undetected. This masking effect is concerning because untreated B12 deficiency can lead to irreversible nerve damage, affecting the brain and nervous system.
Elevated folate, especially when coupled with low vitamin B12, has been associated with neurological and cognitive concerns. Studies have shown that individuals with this combination may experience lower cognitive function scores and an increased likelihood of cognitive impairment. Symptoms such as irritability, forgetfulness, and difficulty concentrating have been reported, and some research suggests a link to brain atrophy in older individuals with B12 deficiency. Peripheral neuropathy, characterized by tingling or numbness in the extremities, is another neurological symptom that can be exacerbated by high folate in the presence of B12 deficiency.
Research suggests effects of high folate on immune system modulation. Excessive folic acid intake has been observed to negatively impact innate immunity, specifically reducing the cytotoxicity of natural killer (NK) cells, which defend against viral infections and cancer. Studies suggest a causal link between high folic acid intake and lowered NK cell activity, suggesting increased susceptibility to certain diseases. Some studies have also linked prenatal folic acid supplementation to an increased risk of childhood asthma, though findings in this area are not uniformly conclusive.
The relationship between high folic acid intake and cancer risk is complex and an area of ongoing scientific investigation. While some studies suggest an increased risk of certain cancers, such as prostate or colorectal cancer, with high folic acid supplementation, other research indicates neutral or even protective effects. A recent study found an association between high-dose folic acid use and increased overall cancer risk, with a consistent link to non-Hodgkin lymphoma. However, the absolute risk of cancer remains low, and overall research findings are conflicting, requiring further prospective studies to clarify optimal levels for cancer risk reduction.
Addressing High Folate Levels
If blood tests indicate elevated folate levels, consulting a healthcare professional is important for proper diagnosis and personalized recommendations. A comprehensive assessment includes blood tests for both folate and vitamin B12 levels to confirm the elevation and rule out any concurrent deficiencies, especially B12 deficiency. This dual testing helps ensure that any underlying conditions are identified and addressed.
A common approach to managing high folate is through dietary adjustments. Reducing the intake of foods fortified with folic acid, such as certain cereals and breads, can help lower overall folic acid consumption. While natural food folate is considered safe, minimizing excessive intake from fortified sources can help bring levels back into a healthy range.
Reviewing and adjusting or discontinuing folic acid supplements is another important step, always under medical supervision. Excessive supplementation is a frequent cause of high folate, so a healthcare provider can advise on appropriate dosages or alternative forms of folate if supplementation is still needed. This tailored approach helps prevent further accumulation while ensuring adequate nutrient intake.
When an underlying medical condition, such as kidney disease or pernicious anemia, is identified as contributing to elevated folate levels, managing that condition becomes a primary focus. Treatment for these conditions can help regulate folate metabolism and excretion, thereby addressing the root cause of the high levels. Management strategies are always individualized, considering the specific cause of the elevated folate and the person’s overall health status.