Is there a gene that protects people against heavy drinking, alcoholism, drug addiction, or even the desire to drink alcohol because the taste and smell of alcoholic beverages aren’t appetizing or thirst-quenching? Or are you perhaps surrounded by an environment that encourages drinking, for example, on campuses or when you go out with friends to local night life events, how much alcohol do you like to drink with your food?
And has the wine or beer drinking (or preparing) tradition been in your family for generations? Would you rather cook with wine or drink it? How do you know whether you’ve inherited a specific type of gene/allele to protect you against alcoholism by making alcoholic drinks taste pretty bad in your mouth or smell like some type of cleaning chemical?
Can you predict which groups in your circle of friends, people in the news, or even some of your relatives will drink the most without becoming violently ill fastest? Scientists are studying why some ethnic groups drink far less than others and whether the environment influences drinking habits or whether genes override the environment. Does Sacramento encourage drinking among certain age groups or even specific ethnic groups? If not, why? And if so, what’s the payoff for drinking socially in Sacramento? Let’s look at some scientific ethnic studies on genes and alcoholism.
Which groups have the lowest rates of alcoholism because they aren’t craving fermented alcoholic beverages or because their tradition didn’t emphasize drinking beer, whiskey, or wine?
Scientists surmise that maybe some of the answers turn up in studies the genes of some Eastern European Jewish families who have very low rates of alcoholism even though for centuries they lived next to neighbors in Russia or Poland who drank more alcoholic drinks because it tasted differently to one group than the alcohol did to the other group. Do your genes determine whether you want to drink an alcoholic beverage based on how it tastes and smells to you? How do your genes keep you from drinking too much?
Is there a protective gene variation that steers some people away from the desire to imbibe?
Do you have the gene variation that protects against alcoholism? The two peoples most likely to have gene variations that protect against alcoholism are Jews descended from ancestors who lived in Eastern Europe, peoples genetically related to them, and other Middle Eastern peoples.
Also see the article, Health-Related Effects of Genetic Variations of Alcohol – NIAAA. According to this study, alcohol avoidance is not just about taste, it’s about symptoms experienced after drinking a small amount of alcohol by some who immediately feel a rapid heartbeat and nausea after drinking a small amount of alcohol. Alcohol metabolism is one of the biological determinants that can influence drinking behavior and the development of alcohol dependence and alcohol-induced organ damage (Yin and Agarwal 2001).
What happens in oxidative alcohol metabolism?
Oxidative alcohol metabolism depends on two key enzymes—alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH). ADH converts alcohol to the highly toxic metabolite acetaldehyde, which then is metabolized by ALDH to acetate and eventually to carbon dioxide (CO2) and water.
For both ADH and ALDH, several variants (i.e., isoforms) exist that differ in their ability to break down alcohol and acetaldehyde, respectively. For example, certain ADH isoforms are particularly active and rapidly break down alcohol to acetaldehyde. Conversely, certain ALDH isoforms have very low activity and break down acetaldehyde slowly.
In both of these cases, acetaldehyde will accumulate after alcohol consumption, exerting its toxic effects by causing a flushing syndrome characterized by facial flushing, nausea, and rapid heartbeat. These effects deter people from alcohol consumption and therefore have a protective effect against alcoholism. How do you know whether you have the gene that keeps you from drinking alcohol by making you feel sick when you start to drink alcoholic beverages?
Is there a gene that allows some people who do drink to imbibe more responsibly than others?
Could you have inherited a gene that protects you from becoming alcoholic or drinking irresponsibly? According to a study from the American Journal of Psychiatry, “Alcohol and ADH2 in Israel: Ashkenazis, Sephardics, and Recent Russian Immigrants.” (See, the American Journal of Psychiatry 159:1432-1434, August 2002.) There’s an old Yiddish saying, “Shikka as a goy.” It means “drunk as a non-Jew.” And this saying, common in 19th century Russia compared drinking habits between Russians and Jews living in Russia (or Poland, Lithuania, Latvia, or Belarus).
What did it really mean? It meant if someone got drunk, it usually would be someone not from a Jewish family? Why? Because in those days, drinking alcohol at least in excess was likely to make the person with the most Middle Eastern (or Asian) genes feel flushed, nauseous, and develop a rapid heartbeat. Whereas with others without the gene, drinking created other changes in behavior rather than flushing and nausea.
What other groups may have inherited genes that discourage them from getting drunk? Or is prevention of alcoholism merely cultural based on tradition?
Some other groups may also have inherited such genes. It’s not by accident, for example, that in the Middle East Islam forbade drinking alcohol. People with a lot of Middle Eastern genes just don’t drink very much (unless they’ve also inherited lots of European genes as well.) The same can be said for people of Far Eastern descent and some African Americans.
Who lacks genes that warn them not to drink to much? Possibly Native Americans who diverged from Far Eastern peoples tens of thousands of years ago, and Europeans who for thousands of years have fermented grains and grapes to make beer and wine. But with mixing of peoples, only you know whether you’ve inherited the gene that protects against alcoholism or whether alcoholism runs in your family.
This study, “Alcohol and ADH2 in Israel: Ashkenazis, Sephardics, and Recent Russian Immigrants,” indicates a protective role against heavy drinking in Jewish individuals, for the people who have the gene (allele) variation called ADH2*2, which may partially explain the low levels of alcoholism among people who have this genetic inheritance. An allele in genetics is either of a pair (or series) of alternative forms of a gene that can occupy the same locus (place) on a particular chromosome and that control the same character. For example, some alleles are dominant over other alleles.
What group drinks alcohol less than others? Is there an allele that protects against heavy drinking?
Jews drink less than other Caucasians and have a higher prevalence of ADH2*2, an allele of an alcohol dehydrogenase gene that protects against heavy drinking. The relationship of ADH2 polymorphisms to lifetime maximum number of drinks per occasion was investigated in recent Russian immigrants to Israel (exposed to heavier drinking in their country of origin), other Israeli Ashkenazis, and Sephardics.
Seventy-five randomly sampled Israelis participated in a structured interview. ADH2 was genotyped for 68 subjects. ADH2*2 predicted less drinking; however, associations between ADH2 and drinking appeared to differ across the groups, consistent with differences in environmental exposure to heavy drinking.
What’s the protective effect of a gene variation known as ADH2*2?
The findings support a protective effect for ADH2*2 against heavy drinking in Jewish samples but also suggest the importance of environment. Future work should investigate interactions between genes and the environment in larger samples.
Jewish individuals have low rates of alcoholism (See this study), but little is known about influences on their drinking behavior, which may ultimately prove informative about alcoholism in general. Alcohol dehydrogenase is the principle enzyme for ethanol oxidation (See that study). A functional polymorphism of the alcohol dehydrogenase genes, ADH2*2, has been shown to protect against alcoholism (See that study). ADH2*2 occurs in approximately 30% of Jewish individuals (See this other study, and check out this study also), suggesting an explanatory role for ADH2 in drinking by Jews. However, the relationship of ADH2*2 to drinking in Jews varies, according to those studies, possibly because of environmental influences or methodological variation. Studying contrasting Jewish groups with consistent methods should provide clarification, according to the study.
Do some people in certain countries drink more alcohol than other individuals in different nations as a tradition?
Russia’s per capita alcohol consumption level is very high, while Israel’s is very low. Until recently, the two main subgroups of Israeli Jews were Ashkenazis (European/Russian background) and Sephardics (Middle Eastern/North African background), who differ in drinking patterns (See this study). Since 1989, approximately 720,000 new immigrants from the former Soviet Union have arrived in Israel, now forming a third group, scientists noted in the study.
Recent Russian immigrants drink more than other Israelis (See this study). Therefore, ADH2*2 and drinking were studied in these three contrasting Israeli groups in that study. Scientists examined genotype and drinking in contrasting Jewish Israeli groups. Greater drinking among the Russian immigrants supported the validity of the drinking measure. The prevalence of the ADH2*2 allele was high, especially among Sephardics, and was found to protect against heavy drinking when we controlled for confounders.
The prevalence of a phenotypic trait or disease and an allele can both be elevated in a population subgroup for unrelated reasons. When this is undetected in a sample, population stratification can confound research results (Check out that study).
In this study, confounding due to population stratification was unlikely because we controlled for three main groups. Since a higher number of strata lowers the likelihood of confounding (See this other study), the fact that the subjects in this study reported 18 different countries of origin minimized the likelihood of confounding due to population stratification.
In the recent Russian immigrants, exposed to an environment of heavy drinking before immigration, the effect of ADH2*2 appeared different, according to the study. Future studies with larger samples should specifically investigate the interaction of ADH2*2 and environmental influences on alcoholism. Such research may enhance the understanding of both genetic and environmental causes of disease.
What does this mean for specific genes that protect against eating too much or drinking too much alcoholic beverages?
Basically, people inherit genes/alleles that make certain foods and drinks either taste inviting or don’t taste like you’d want to sample a particular food or beverage. For some people, no ethnic group in particular, even vegetables taste bitter at the back of the tongue, whereas other people enjoy chewing their raw veggies.
So research continues on what peoples of the world eat or drink by preference or by genetic predispositions to the taste or feeling obtained from the food. Do you think the idea of alcoholism or no desire to drink, or drinking socially and responsibly runs in your family due to culture, tradition, or genetic inheritance?