metabolism?

Question

is it true that usually younger adults have faster metabolism? So if young people get cancer, the tumor grows much faster because of the better metabolism. is this true? Also the faster metabolism of younger people to seroconvert for HIV faster because their metabolism is faster. Is this true?
however faster metabolism means better nutrition for cells including cancer cells so wouldnt it make cancer cells grow faster and other body activity to speed up than older people with slower metabolism

Answer 1

The reason that cancers in younger people can, at times, be more aggressive than cancers in older people is that the types of cancer processes that occur in younger people are ones in which there has been an early and aggressive genetic change, sometimes due to a hereditary predisposition to cancer mutations. Many of the more common modes of carcinogenesis (cancer formation) are processes that involve sequential mutations in a cell line over many years, and this is why these diseases are more commonly found in the elderly.

The concept of "metabolic rate" is a collective property involving many different things going on in the body at the same time. In some ways, it's a lot like considering the average IQ at a university. Knowing the average IQ at a university will not help you predict how a specific small group will do when they take the final exam for one class. In the same way, the concept of metabolic rate is so broad that it scarcely has utility when considering what happens at the level of individual physiologic processes. Metabolic rate is a useful concept when trying to supply adequate but not excessive amounts of nutrition to sick people. Thats its main utility.

Answer 2

Correct Premise: BMR (Basal Metabolic Rate) is higher in young people. Incorrect Premise: Seroconversion for HIV occurs faster in young people. (Too many variables to consider to make such a generalized statement.) Lastly, only some cancers will grow faster in the young. Again, a statement that is too general to satisfy all variables. For example, cancer of the thyroid may wreak havoc with the last two answers.