On basic terms, nothing in your control can cause HD. You can not develop it because of foods you eat, or things you do. This particular disorder happens to not come into affect until ages 30-40 usually, even though the people that have it were born with it. Genetically speaking, on the short leg of the 4th chromosome, on the HTT gene, there is normally a sequence of repeating bases CAG. So it is normally CAGCAGCAGC... anywhere from 10-35 times, however, if it repeats 36-120 times, HD is developed. The more repeats, the earlier HD will come into your life. Some people with 100 repeats will start showing symptoms for HD at age 20, while others with 36-80 repeats won't start seeing the symptoms until ages 30-40.