You might be wondering whether it would be easier to wait for medicine to develop high-tech gene therapies to correct any genetic weaknesses you have or might develop as you age. The problem with that line of thinking is that you may be dead before such research produces any benefits for the majority of people.
（66） For example, reports of a “breast-cancer gene,” a “heart-disease gene”, or an “obesity gene” suggest that a single faulty gene causes each of these diseases. If this were the case, it might be relatively easy to develop gene therapies. But the “one gene, one disease” view is overly simplistic. （67） The truth is that only a very small number of people have “smoking gun” genes that predispose them to obesity, diabetes, heart disease, Alzheimer’s disease, or other disorders.
Although you don’t read about it very often, genetic research has clearly shown that degenerative diseases are actually “polygenic”. （68） Up to 5,000 malfunctioning genes set the stage for cardiovascular disease, almost 300 wayward genes are involved in asthma, and 140 faulty genes contribute to the problem of failing memory. And with the complex interplay of 30,000 genes and 3 billion units of DNA, it may very well be impossible ever to design truly effective multi-gene therapies to treat common diseases.
（69） In most instances they have simply failed to work, and sometimes patients have developed cancer or died from mysterious causes. For example, many researchers have used genetically modified viruses to deliver disease-treating DNA. In some human experiments, these viruses missed their target and instead attached to the wrong gene, causing leukemia. （70）
The massive research effort to turn gene therapy into a marketable product has for the most part ignored how genes depend on proper nourishment. Many scientists have been forced to accept the fact that thirty thousand genes cannot by themselves account for the phenomenal complexity of the human body. It is now becoming clear that vitamins and other nutrients directly and indirectly serve as cofactors in gene activity.
A. That is, most diseases involve hundreds and sometimes thousands of genes that go wrong.
B. But the science behind nutrition and genetics is solid, and nutrition has the advantage of helping without causing harm.
C. The reason is that a lot of gene research has been misguided by wishful thinking and oversold to investors and the general public.
D. The consequences of manipulating genes are often unpredictable, largely because of their inherent complexity.
E. Another problem is that despite billions of dollars of research, gene therapies have so far been an utter failure.
F. Only about 10 percent of women with breast cancer have one of the so-called breast-cancer genes.
