BHT

What Is BHT? 

BHT or butyl hydroxytoluene is a fat soluble synthetic compound which is commonly used to preserve foods and cosmetics to slow down the autoxidation rate of ingredients in a product that can cause changes in the taste or colour. As such, it is primarily used to prevent fats in foods from becoming rancid – but it is also used in cosmetics, pharmaceuticals, jet fuels, rubber, petroleum products, electrical transformer oil, and embalming fluid.

Sure sounds strange that  BHT is something that is found in our food, right?

BHT

It has been the subject of many studies, which have been contradictory in their findings. The result is that we are left with confusion over whether consuming and applying products containing BHT is safe. This confusion is nothing new, as we can see from the following excerpt from Business Week magazine back in 1995.

Several additives are suspected carcinogens. Take butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT). Food companies use these similar chemical substances to prevent spoilage in foods with oil or shortening and to preserve many breakfast cereals (from Total to Quaker Instant Oatmeal), enriched rice products, and dried soups. Repeated studies have shown that BHA and BHT increase the risk of cancer as well as accumulate in body tissue, cause liver enlargement, and retard the rate of DNA synthesis and thus, cell development. However, one study, released in 1994, suggests these same additives may actually retard cancer development because of their antioxidant properties.
There is actually more than one study suggesting anti-carcinogenic effects of BHT. This article aims to look at the conflicting conclusions to help individuals to make informed choices regarding purchasing these products.

Dangers of BHT

When looking at the MSDS (Material Safety Data Sheet) for BHT we found the following:

• Do NOT let this chemical enter the environment.
• Combustible.
• Ingestion causes Abdominal pain. Confusion. Dizziness. Nausea. Vomiting.
• The substance may have effects on the liver.
• The substance is harmful to aquatic organisms.

BHT As A Cause of Cancer

There have been many studies which demonstrate that BHT accumulates over time in the body, having a toxic impact on the lungs, liver and kidneys amongst other negative effects. We will look chronologically at their findings.

A study by Gann in 1984 showed that BHT was capable of promoting chemically-induced forestomach and bladder cancer in male rats.

This was followed in 1986, with a chronic study on BHT in rats by Olsen.  Dose-related increases in the numbers of hepatocellular adenomas and carcinomas were statistically significant. As with Gann’s study, the doses given to the rats were higher per pound of body weight than we would consume.

A 1988 Swedish study by Thompson looked at both BHT and BHA. They found that both were toxic and tumour promoting.  Both antioxidants were observed to be cytotoxic in a concentration-dependent manner at concentrations ranging from 100 to 750 microM. At equimolar concentrations BHT was more cytotoxic than BHA.

Safer et al conducted a further study on rats in 1999 and came up with the same results. The food additive, butylated hydroxytoluene (BHT), encourages the development of tumors from previously initiated cells.

In 2001, Bauer et al found that lung tumor formation was promoted by BHT administration following an initiating agent in BALB/cByJ mice, but not in CXB4 mice. So in those mice that had a sensitivity to BHT, it caused chronic inflammation and promoted lung tumours.
A study published in 2006 in Argentina, used hamsters to prove that BHT did not prevent cancer but rather did the opposite. Results obtained showed that BHT did not decrease the chromosomal damage induced by radiation in any consistent fashion. On the contrary, in cells post-treated with 5.0 µg/ml of BHT the yield of chromosomal aberrations increased in several experimental points.

It is also pretty clear in the following excerpt from a study by the University of Hamburg that BHT is tumour promoting.

“Specific toxic effects to the lung have been observed with BHT…. BHT induces liver tumours in long-term experiments. Because there is no indication of genotoxicity of BHT, all published findings agree with the fact that BHA and BHT are tumour promoters. In contrast to BHA and BHT, vitamin E is not carcinogenic. On the other hand, all three antioxidants have also anticarcinogenic properties. The intake of the necessary high doses as for these effects are, however, contraindicated with BHA and BHT because of their carcinogenic effects.”