Are your parents heavy drinkers? Whether you can hold your alcohol or not is determined by a couple of genes.
Alcohol is not that harmful, but acetaldehyde, the substance produced when alcohol is decomposed in the body, is very poisonous, and it can make you feel sick when there is too much acetaldehyde in the body; you should have experienced a hangover.
Therefore, acetaldehyde must be decomposed quickly. Enzymes decompose the substances in our body, and enzymes are produced according to genetic coding (SNP).
If you don’t have a particular gene for the enzyme that has a function to breaks down acetaldehyde, you will not be able to decompose acetaldehyde, and you will feel sick soon after drinking alcohol, even with a little amount.
That is whether the type of genes your parents have determines that you are strong against alcohol or not. Also, genetic diversity differs depending on region or ethnicity. East Asians are known to have particular SNPs that makes them weak against alcohol. In comparison, white and black populations are known to be stronger against alcohol.