Folic Acid linked to cancer?

I am about to start using Huel to substitute one or two meals a day. I am generally impressed by the nutritional content. I have no qualifications but, with my wife, am an amateur nutritionist and follow a largely vegan diet based on the books and advice of the American doctor and nutritionist Dr Joel Fuhrman. My diet is largely intended to reduce the long-term risks of cancer.

My concern is the addition of Folic Acid as an ingredient to Huel. Joel Fuhrman strongly advises against any supplements containing Folic Acid due to links to various forms of cancer. Dr. Fuhrmen quotes many research studies in this article:

I have built up a lot of trust in the advice from Dr. Fuhrman and would be interested in any views and opinions regarding the use of Folic Acid as a supplement because is may well stop me from taking Huel if I am not reassured that it is safe.

The addition of folate to Huel is to bring it up to the required amount for good health - without adding it, we couldn’t claim Huel as ‘nutritionally complete’.

I consider that advice in the link you provided to be questionnable and possibly dangerous. The evidence for folate supplementation and the reduction of risk of spina bifida is very well researched with many well-designed studies. The are questions in that research I have: do the studies he cites adjust for other factors associated with increased breast cancer risk, like age of first and last full term pregnancy? Were the ladies taking set amounts of folate supplementation or were some supplementing with more than others?

I’d be very cautious in putting too much trust in one writer: sure, read their stuff and take it on board, but read other info too.


James, thanks for your reply.

Fuhrman is not denying the benefits of folate but is wary about taking synthetic folic acid as a supplement. In his words “The synthetic folic acid found in supplements is chemically different from food folate, which is abundant in green vegetables, beans and other plant foods. Folate is especially important for women of childbearing age, to prevent against birth defects. However, women who take synthetic folic acid in multivitamins may be at increased risk of breast cancer. Folic acid supplementation also raises the risk of prostate and colorectal cancers. Folate in its natural form protects against breast and prostate cancers.”

Fuhrman has a range of supplements and these provide folate in the form of a Whole Food Fruit, Veggie and Greens blend which provides the folate in a natural form. Is there any reason why Huel could not be formulated to provide folate in this more natural form?

Further information is here:

I’m really sorry but this makes me sceptical:

Fuhrman has a range of supplements and these provide folate in the form
of a Whole Food Fruit, Veggie and Greens blend which provides the folate
in a natural form.

Without me scrolling through his site for ages, is there a bit where he demonstrates actually why the form of folic acid in his supplements is better?

Referring to your previous post, I do not know the answers to your questions about the research quoted by Fuhrman as I have not myself read the research papers. However, since they are peer reviewed and published in such journals as the ‘British Medical Journal’ and the ‘Journal of the National Cancer Institute’ I would have assumed that any biases would have been taken account of unless I had some evidence to the contrary. I would certainly not dismiss them out of hand and assume that they must have some bias because the results are contrary to conventional wisdom.

With regard to the evidence for Fuhrman’s use of a ‘whole foods blend’ as a way of supplementing folate, I have been unable to find any evidence on his website that specifically explains this. However, if there is evidence that synthetic folic acid promotes cancer and there is no evidence that natural folate promotes cancer then is it not a no-brainer that the natural form is preferable.

There is an article on Fuhrman’s website which reports on research that indicates that since folic acid was added to flour in Chile there has been an increase of colorectal cancer (although of course this does not prove cause and effect). The article quotes Dr Joel Mason, MD from the Jean Mayor US Department of Agriculture Human Nutrition Research Center as saying “habitually high intakes of dietary folate are protective against colorectal cancer.” However, the pharmaceutical form of folate i.e. folic acid, which is used in fortification of foods and in vitamin tablets) might act differently than dietary folate, and they note that there is literature to suggest that a high intake of folic acid can accelerate the growth of established neoplasma. Adding substantial quantities of folic acid to the food supply in the mid-1990s might have facilitated the transformation of colorectal adenomas (which are found in 35% to 50% of Americans) into larger cancers, they suggest.

Not being an expert in nutrition or a chemist, I do not understand the difference between folic acid and folate but Fuhrman and Dr. Mason do appear to distinguish between the two. From what I have read it seems that folate is a natural substance that has health benefits and (if taken in sensible quantities) has no known negative qualities. However, folic acid is a synthetic substance which mimics folate and has the benefits of folate but there is evidence that it may promote certain forms of cancer.

I would reiterate that Fuhrman is not disputing that folate is a necessary element to good nutrution, he is arguing that taking folate in the form of folic acid may also have negative effects i.e. increased risk of certain cancers. Whether the benefits outweigh the possible risks is uncertain but if there are alternate forms of taking folate where there is no evidence that they increase the risk of cancer then surely these are preferable?

Terms like “natural” are provocative, it’s true. Specifically, the different supplements in question are folic acid versus 5-methyltetrahydrofolate. Both are currently available as dietary supplements.

A brief googling indicates that there is some evidence that 5-methyltetrahydrofolate may be preferred.

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