What is Folate Metabolism?

Folate, and its synthetic form folic acid, is a water-soluble B vitamin that plays a fundamental role in a variety of functions in the human body. Folate is essential for cell division and homeostasis because it acts as a coenzyme in many biological pathways, including amino acid metabolism, methionine production, and DNA methylation. Folate metabolism happens together with the methionine cycle and the choline pathway. Most folate coenzymes are found in the liver.

Folate is also used as a coenzyme to convert methionine into homocysteine. Vitamin B6 and B12, together with folate, are also essential for DNA synthesis. Proper dietary intake of folate is fundamental for normal cell growth and DNA repair. Folate or vitamin B12 deficiency can ultimately cause a variety of health issues, including anemia. Oral supplementation may be necessary. In the following article, we will discuss folate metabolism and foods that are high in folate.

Folate Metabolism Overview

Several of the most important functions of folate metabolism are methylation and S-adenosylmethionine (SAM) production, one of the most essential methyl donors in the cell. In the following diagram, we will explain folate metabolism. 

Figure 1: One carbon metabolism. ATP: adenosyl triphosphate, B6: vitamin B6, B12: vitamin B12, BHMT: betaine homocysteine methyltransferase, CBS: cystathionine-β-synthase, DHF: dihydrofolate, DMG: dimethylglycine, dTMP: deoxythymidine monophosphate, dUMP: deoxyuridine monophosphate, Gly: glycine, Hcy: homocysteine, MAT: methionine adenosyltransferase, Met: methionine, MCM: L-methylmalonyl CoA mutase, MM-CoA: L-methylmalonyl CoA, MMA: methylmalonic acid, MS: methionine synthase, MTHFR: 5,10-methyltetrahydrofolate reductase, SAH: S-adenosyl homocysteine, SAHH: S-adenosyl homocysteine hydrolase, SAM: S-adenosyl methionine, Ser: serine, SHMT, serine hydroxymethyltransferase, THF: tetrahydrofolate, TS: thymidylate synthase. Adapted from: Hypo- and hypervitaminosis of B and D vitamins – Diagnosis and clinical consequences. Herrmann W. et al. 2013. Uni-Med Verlag AG.

Dihydrofolate reductase (DHFR) is a component that converts folate to dihydrofolate (DHF) and DHF to the active form, THF. Folate metabolism consists of three cycles. One cycle starts with a component known as 10-formylTHF which is associated with purine production and two cycles utilize 5, 10-methyleneTHF in deoxythymidine monophosphate (dTMP) and methionine production. 5-MethylTHF is one of the most predominant forms of folate found in the human body.

After cellular uptake, 5-methylTHF is converted into THF through the use of vitamin B12 in methionine synthase (MS). The methionine cycle is a fundamental pathway in SAM production. As previously mentioned above, B vitamin deficiencies, including folate, vitamin B6, and B12, as well as genetic birth defects can ultimately cause a variety of health issues. 5,10-MethyleneTHF is finally converted to 5-methylTHF by 5,10-methylenetetrahydrofolate reductase (MTHFR).

Several of the most important functions of folate metabolism are methylation and S-adenosylmethionine (SAM) production, one of the most essential methyl donors in the cell. In the following diagram, we will simplify folate metabolism. 

15 Foods That Are High in Folate

Folate, and its synthetic form folic acid, is a water-soluble B vitamin that plays a fundamental role in a variety of functions in the human body. It supports cell division and promotes fetal growth and development to reduce the risk of genetic birth defects. Folate is naturally found in many different types of foods. Doctors recommend 400 mcg of folate every day for adults to prevent deficiency. Here are 15 healthy foods that are high in folate or folic acid, including:

• avocado
• bananas
• citrus fruits
• papaya
• beets
• leafy greens
• asparagus
• Brussels sprouts
• broccoli
• nuts and seeds
• legumes
• eggs
• beef liver
• wheat germ
• fortified grains

In conclusion, folate, and its synthetic form folic acid, is an important micronutrient that can be naturally found in many different types of foods. Eating many different types of healthy foods, including fruits, vegetables, nuts, and seeds, as well as fortified foods, is an easy way to increase your folate intake. These foods are not only high in folate but these are also high in other essential nutrients that can ultimately improve other aspects of your overall health.

For information regarding the nutritional role of folate, please review the following article:

Nutritional Role of Folate

Folate or folic acid is a water-soluble B vitamin that plays a fundamental role in a variety of functions in the human body, including cell division and homeostasis. Folate also helps with amino acid metabolism, methionine production, and DNA methylation. Folate or vitamin B12 deficiency can ultimately cause a variety of health issues. Oral supplementation may be necessary. In the diagrams above, we explain the process of folate metabolism. Folate is naturally found in many different types of foods, including avocado, citrus fruits, leafy greens, broccoli, nuts and seeds, legumes, eggs, and fortified grains. Eating many different types of healthy foods is an easy way to increase your folate intake. These foods are not only high in folate but these are also high in other essential nutrients that can ultimately improve other aspects of your overall health. – Dr. Alex Jimenez D.C., C.C.S.T. Insights

Almonds have twice as much calcium as milk

Gram for gram this is absolutely true! According to McCance and Widdowson’s Composition of Foods (the official guide to the nutrients in food used in the UK), about 100g of almonds have 240mg of bone-building calcium while semi-skimmed (2%) milk has 120mg per 100g (3.5oz). With that being said, however, we tend to drink milk in bigger quantities than we eat almonds (and the calcium from milk is easily absorbed), so the dairy option may be a better source day-to-day.