Folate is part of the family of B vitamins and must be consumed daily. Ongoing debate over whether or not to fortify staple foods with folic acid, has led researchers to investigate other strategies for improving the folate status of Europeans.

Why we need folate

Folate is needed in the synthesis, repair and functioning of DNA and RNA, the basic building blocks of life. Thus folate is required for the production and maintenance of new cells and is particularly important during periods of rapid growth such as infancy and pregnancy. Both adults and children need folate to make normal red blood cells and to prevent anaemia(1). Marginal folate deficiency is also linked to elevated blood levels of the amino acid homocysteine which is an emerging risk factor for heart disease and stroke(2). As folate helps prevent damage to DNA there is some evidence it may prevent certain cancers, notably colon cancer(3).

Food sources of folate

It is recommended that adults consume 200 micrograms of folate per day. Dietary sources include; orange juice, dark green leafy vegetables, peanuts, beans, pulses and offal. To avoid marginal folate deficiency it is a good habit to consume at least five portions of fruit and vegetables a day (see www.5aday.com).

Folic acid supplements

Folic acid is a simple and easily absorbed man-made form of folate. In the early 1990s powerful evidence demonstrated that women who took folic acid supplements around the time of conception more than halved the risk of bearing babies with neural tube defects like spina bifida(4). Public health campaigns were launched across Europe to encourage women of child bearing age to boost their intake of folate rich foods and take folic acid supplements (400 micrograms/day). However these campaigns had limited success, not least because women tend to make dietary changes only after they are aware they are pregnant i.e. a few weeks after conception. By this time it is already too late.

Fortification of foods

An alternative strategy is the fortification of basic foodstuffs, such as flour, with folic acid. This way all women of child bearing age would receive adequate folic acid, as would all those at risk of cardiovascular disease. However this strategy has not been adopted in Europe mainly over concern that high doses of folic acid may not be beneficial for the whole population. In particular folic acid can mask symptoms of the anaemia associated with B12 deficiency and the resulting changes in the nervous system that can lead to permanent nerve damage(1). Folic acid supplements may also interfere with certain cancer treatments(5).

Increasing food folate

So scientists are looking at other ways to enhance folate intake. One area of particular interest to the EU funded Folate FuncHealth team(6) is how to increase consumption of natural folates from food. Here are some of their findings(7):

• The level of folate in fermented products like bread, beer and wine can be increased by choosing folate-rich strains of yeast.
• Other fermentation microbes, including lactic acid bacteria, also synthesize folate. The correct choice of starter culture can produce a 20 fold increase in the folate content of fermented dairy products like cheese and yogurt.
• The folate content of processed foods like soup and fruit juices can be improved by choosing folate-rich varieties of fruits and vegetables and using milder processing techniques which result in smaller folate losses.
• Folates are concentrated in the outer parts of the cereal grain thus using a milling technique that includes this folate-rich fraction can increase the folate content of flour.

Still not enough

It is estimated that advances in food processing techniques and selective choice of folate boosting ingredients could double our current folate intake, but this is still not enough! Dr Paul Finglas from the UK Institute of Food Research and coordinator of the FoodFuncHealth project believes… 'it is difficult to consume enough natural folate from a balanced diet to ward off chronic diseases like cancer and heart disease. Some form of low level fortification or targeted supplementation will be needed.
A full review of recommendations based on the findings from the FoodFuncHealth(8) project are soon to be published and will be available on the website(6) thereafter.

References

1. UK Food Standards Agency at www.eatwell.gov.uk/healthydiet/nutritionessentials/ vitaminsandminerals
2. Strain JJ. Dowey L. et al (2004) B-vitamins, homocysteine metabolism and CVD. Proceedings of the Nutrition Society. 63; 597-603
3. Duthie SJ. Narayanan S. et al (2004) Folate, DNA stability and colo-rectal neoplasia. Proceedings of the Nutrition Society. 63; 571-578
4. MRC Vitamin Study Research Group (1991) Prevention of neural tube defects; results of the Medical Research Council Vitamin Study. The Lancet 338; 131-137
5. Peters GJ, Hooijberg JH, et al (2005) Folates and anti-folates in the treatment of cancer; role of folic acid supplementation on efficacy of folate and non-folate drugs. Trends in Food Science and Technology 16;289-297
6. FolateFuncHealth and EU funded pan EU project. For details visit www.ifr.ac.uk/Folate
7. Jägerstad M. Piironen V. et al (2005) Increasing natural food folates through bioprocessing and biotechnology. Trends in Food Science and Technology 16: 298-306
8. Finglas PM de Meer K. et al (2005) Research goals for folate and related B-vitamins in Europe. European Journal of Nutrition in press

FOOD TODAY 01/2006