Esophageal Cancer Risk Factors
ALDH2 Deficiency and Selenium
Jacob Schor ND FABNO
April 15, 2009


Some people flush bright red after drinking even the smallest amount of alcohol. According to research published in March, these people are at higher risk of developing esophageal cancer. This tendency to flush from alcohol is a biomarker of an inborn deficiency of an enzyme named aldehyde dehydrogenase 2 (ALDH2) that is required to break down alcohol. About one third of people in East Asia are born deficient in this enzyme. They flush red and can experience nausea and their hearts start beating fast if they drink. This genetic trait, not having the proper gene for ALDH2 puts people at an increased risk of developing esophageal cancer. Clinicians are now encouraged to watch for this trait and warn susceptible individuals that the risk alcohol poses to them. [1]



Of course one must wonder how many people will actually change their alcohol consumption based on this knowledge. Even if we can’t get these people to stop drinking, it may be possible to get them to take selenium. In a study published in the July 2006 issue of Cancer, researchers reported the effect ALDH2 deficiency had on esophageal cancer risk with or without selenium deficiency.


Having the wrong gene and being ALDH2 deficient doubles risk of esophageal cancer. [The ALDH2 Lys. variant alleles were associated with an increased risk of ESCC with adjusted ORs of 1.91 (95% CI, 0.96-3.80) and 1.67 (95% CI, 1.08-2.59), respectively]


People who get relatively high amounts of selenium in their diets as calculated from food questionnaires are at about half the risk of getting esophageal cancer as those who get low amounts of selenium. [The adjusted odds ratio (OR) for the highest quintile of dietary selenium intake, compared with the lowest
quintile of intake, was 0.48]



When you put the two together, the effects are multiplied. People with both ALDH2 deficiency and inadequate selenium in their diets are at quadruple the risk of getting esophageal cancer. [2]


The take home message, if your face flushes red when you drink, you probably shouldn’t drink. Whether you choose to abstain or not, you should make a point of eating foods high in selenium or take a selenium supplement. The best food to eat to easily obtain adequate selenium are Brazil nuts.



Drinking hot tea is another risk factor that increases chance of getting esophageal cancer. Also published in March this year is an Iranian study on drinking and risk of esophageal cancer. There are areas of Iran where almost everyone drinks hot tea almost all day. Smoking is rare and alcohol consumption is even rarer. Thus it is possible to measure the effect the tea has without the other two major risk factors for this type of cancer. Esophageal cancer was eight times as common among people who drank "very hot" tea, compared to warm or lukewarm tea drinkers. By the same comparison, hot tea drinkers were twice as likely as warm or lukewarm tea drinkers to have esophageal cancer. [3,4]


A similar risk is seen in South America where people who drink matte tea sip it so hot it’s near boiling. [5]

References:

1. PLoS Med. 2009 Mar 24;6(3):e50.
The alcohol flushing response: an unrecognized risk factor for esophageal cancer from alcohol consumption. Brooks PJ, Enoch MA, Goldman D, Li TK, Yokoyama A.  pjbrooks@mail.nih.gov

2. Cancer. 2006 Jun 1;106(11):2345-54.
Dietary selenium intake, aldehyde dehydrogenase-2 and X-ray repair cross-complementing 1 genetic polymorphisms, and the risk of esophageal squamous cell carcinoma. Cai L, You NC, Lu H, Mu LN, Lu QY, Yu SZ, Le AD, Marshall J, Heber D, Zhang ZF.

3. BMJ. 2009 Mar 26;338:b610. doi: 10.1136/bmj.b610. Hot tea and increased risk of oesophageal cancer.
Whiteman DC.
PMID: 19325178 [PubMed - indexed for MEDLINE

4. “Hot Tea May Raise Esophageal Cancer Risk
It's Not the Tea; It's the Temperature -- Scalding Hot Liquid Could Injure Cells in Esophagus, Study Says
By Miranda Hitti
WebMD Health News

5. Cancer Epidemiol Biomarkers Prev. 2003 Jun;12(6):508-13.
Maté consumption and the risk of squamous cell esophageal cancer in uruguay.
Sewram V, De Stefani E, Brennan P, Boffetta P.



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