Whenever I ask my patients if they know about folate, the typical answer is: "yes, that's the one you need it when you're pregnant, right?" Now, of course that is true! However, folate is critical throughout all stages of your life, no matter your pregnancy status, age, or sex. Folate is an essential nutrient and we all need to make sure we are getting enough of it in our diets regularly.
What is folate?
Folate is a member of the essential B-vitamins family (vitamin B9) that is found naturally in many whole foods. Though folate is typically referred to as a single nutrient, it more appropriately refers to a group of nutrients that are all different types of folates. In addition, folate is often interchanged with folic acid. However, it is important to understand that folic acid is the synthetic, inactive form of folate that is added to foods (fortification) and is typically the form found in most supplements. Once absorbed, folic acid must be converted to the activated form of folate that our body can use.
Let’s say someone gives you a macadamia nut that they’ve picked straight from a macadamia tree. The nut is contained in an extremely hard shell. In this raw form, you couldn’t possibly eat the nut nor absorb any of its energy or micronutrients. Before you can eat the nut, you must first go through the tedious processes of roasting the nut and cracking off the shell with a sturdy nutcracker. If you do not have an oven to roast the nut and/or the appropriate tool to break the shell, then you would simply not be able to consume it and the energy and micronutrients would be locked inside the shell. When your body gets folic acid, it’s as if you’ve given it a macadamia nut with its hard shell still on. Your body can convert folic acid to the active form of folate that it can use, but individuals have varying levels of capacity to activate folate depending largely on genetics. For example, inheriting two copies of MTHFR C677T causes a significant reduction in the capacity to convert folate to its most active form. In other words, affected individuals do not carry the appropriate tools to shell the nut and are at an increased risk of becoming deficient in folate, even if their intake of folic acid is high.
Okay, let's stop talking about nuts...
Folate has many vital functions in the human body. It is required for the synthesis, repair and methylation of DNA (1). DNA used to be thought of like a music album being played on repeat – a set sequence of songs that we’d listen to for life. However, the discovery of epigenetics has shown that this is not the case. Epigenetics describes our DNA more like a large orchestra – some instruments are out of tune (“bad” genes) and some genes are in tune (“good” genes). The best part is that it is mostly up to us to direct the symphony that we want to play. Folate enables us to do this through the process of methylation. To “methylate” something can be thought of as flicking the switch on something. To methylate a gene for example, might mean turning that gene “on” (and expressing it) or turning that gene “off” (and not expressing it). Folate is also important in the production of healthy red blood cells and for cell division. This is one of the main reasons why humans require significantly more folate during infancy and pregnancy to support increased growth rates.
How much folate do we need?
The recommended daily intake of folate is 400 micrograms per day for adult males and females (2). This could be achieved with 2 eggs + 100 g cooked asparagus + 50 g of mushrooms over the course of the day. With that said, liver is by far the best source of folate, with 100 grams of chicken liver containing 590 micrograms of folate!
Folate requirements increase substantially during pregnancy, particularly in the earliest stage of growth where the neural tube is formed. It is well understood that low maternal folate status is directly related to neural tube defects. Therefore, women who are planning to fall pregnant and women who are known to be pregnant should aim for a folate intake of 600 micrograms per day (2). During lactation, women should aim for 500 micrograms of folate per day to provide sufficient breast milk folate to their baby (2). The upper limit for folate is specific to folic acid only (the synthetic form of folate). The upper limit for folic acid is 1000 ug per day. Folic acid is found in supplements, including multivitamins and protein powders. It is also fortified in wheat is contained in all products containing wheat. Overconsumption of folic acid is reported to lead to immune dysfunction and has been associated with an increased risk of colon cancer (3, 4). Excessive intake of folic acid can also precipitate or exacerbate a vitamin B12 deficiency – a nutrient vital for proper neurological function (2).
Symptoms & consequences of deficiency
Symptoms of folate deficiency are multi-systemic and can be difficult to distinguish from deficiencies in vitamin B6 and/or vitamin B12, considering the metabolism of these vitamins are closely linked. A serious deficiency in one or more of these B-vitamins can lead to a build up of the amino acid, homocysteine. Elevated homocysteine levels have been associated with severe and life-threatening conditions, such as cardiovascular diseases, neurological conditions, infertility, neural tube defects and miscarriage (5-8). Symptoms associated with a folate deficiency should be brought to the attention of a medical doctor and thoroughly investigated. They include, but are not limited to;
· weakness · fatigue · irritability · headache · difficulty concentrating · shortness of breath · heart palpitations
Dietary sources of folate
With the consideration that many individuals cannot tolerate excessive amounts of folic acid, the foods listed below include only those sources that contain natural folate.
Food - Folate (ug) / 100g
Duck liver, raw - 740
Turkey liver, raw - 670
Chicken liver, raw - 590
Beef liver, raw - 290
Lamb liver, raw - 230
Pork liver, raw - 210
Egg yolk, chicken - 150
Egg whole, chicken - 190
Egg whole, duck - 80
Asparagus, cooked - 150
Seaweed, kelp, raw - 180
Spinach, raw - 200
Spinach, cooked - 150
Turnip greens, raw - 200
Mushrooms, dried - 160
Okra, raw - 150
Brussels sprouts - 100
Broccoli, cooked - 110
Cabbage, raw - 80
Lettuce, raw - 140
Collard greens, raw - 130
Artichokes, cooked - 120
Lentils, cooked - 180
Soybeans, cooked - 110
Edamame - 310
Beetroot, raw - 110
Peanuts, raw - 240
Hazelnuts - 110
Walnuts - 100
Mixed nuts - 100
Sunflower seeds - 240
Sesame seeds - 120
Hemp seeds - 110
Data sourced from the USDA Food Composition Database (9).
Take-Home Points
Folate (vitamin B9) is found naturally in whole foods, while folic acid is synthetically added to processed foods (fortification).
Folate is essential for the repair, synthesis and methylation of DNA.
Folate enables cells to divide, creating new cells such as during pregnancy.
Adults require 400-600 micrograms of folate each day for optimal health.
Genetic mutations (e.g., MTHFR C677T) can affect folate metabolism such that some individuals require a higher intake of folate.
Excess consumption of folic acid (synthetic form) can be harmful and individuals supplementing with folic acid or considering supplementation should consult a qualified health professional to ensure safety.
By Jessica Turton
Accredited Practising Dietitian
This article provides general information from the current scientific evidence base and clinical judgement of the author. It is designed for educational purposes only and should not be substituted for medical advice. The author recommends you seek personally tailored support from a qualified healthcare practitioner before undertaking any major lifestyle change. Book an individualised consultation with a dietitian here.
References
1. Krebs MO, Bellon A, Mainguy G, Jay TM, Frieling H. One-carbon metabolism and schizophrenia: current challenges and future directions. Trends in molecular medicine. 2009;15(12):562-70.
2. National Health and Medical Research Council. Folate [Internet]. 2014 [cited 2018 12 Jun]. Available from: https://www.nrv.gov.au/nutrients/folate.
3. Paniz C, Bertinato JF, Lucena MR, De Carli E, Amorim P, Gomes GW, et al. A Daily Dose of 5 mg Folic Acid for 90 Days Is Associated with Increased Serum Unmetabolized Folic Acid and Reduced Natural Killer Cell Cytotoxicity in Healthy Brazilian Adults. The Journal of nutrition. 2017;147(9):1677-85.
4. Hirsch S, Sanchez H, Albala C, de la Maza MP, Barrera G, Leiva L, et al. Colon cancer in Chile before and after the start of the flour fortification program with folic acid. European journal of gastroenterology & hepatology. 2009;21(4):436-9.
5. Rugolo S. Hyperhomocysteinemia: associated with obstetric diabetes and fetal malformations. Minerva Ginecologica. 2005;57:619-25.
6. Seshadri S, Beiser A, Selhub J, Jacques PF, Rosenberg IH, D'Agostino RB, et al. Plasma Homocysteine as a Risk Factor for Dementia and Alzheimer's Disease. New England Journal of Medicine. 2002;346(7):476-83.
7. Nygård O, Nordrehaug JE, Refsum H, Ueland PM, Farstad M, Vollset SE. Plasma Homocysteine Levels and Mortality in Patients with Coronary Artery Disease. New England Journal of Medicine. 1997;337(4):230-7.
8. Iso H, Moriyama Y, Sato S, Kitamura A, Tanigawa T, Yamagishi K, et al. Serum total homocysteine concentrations and risk of stroke and its subtypes in Japanese. Circulation. 2004;109(22):2766-72.
9. United States Department of Agriculture Agricultural Research Service. USDA Food Composition Databases: Nutrient Lists 2018 [cited 2018 13 Jun]. Available from: https://ndb.nal.usda.gov/ndb/nutrients/report?nutrient1=432&nutrient2=&nutrient3=&fg=13&fg=1&fg=4&fg=15&fg=17&fg=16&fg=12&fg=10&fg=5&fg=11&max=25&subset=0&offset=325&sort=c&totCount=3674&measureby=g.