DEAR DR. BLONZ: What controls the body's ability to make cholesterol, and how much is made? Can we manufacture much more cholesterol than we take in with our food? -- E.D., Palo Alto, Calif.
DEAR E.D.: Even in people without a dietary source, such as strict vegetarians or vegans, the body makes all the cholesterol it needs. This is because cholesterol is an essential structural element in every cell of the body. In addition, cholesterol is a raw material for a number of hormones, including estrogen and testosterone. Many cells in the body can make cholesterol, but much of it gets made in the liver.
There are feedback mechanisms to stop cholesterol production when there is enough; ideally, when cholesterol is absorbed from the foods we eat, the liver and the body's cells will make less. There are a number of genetic conditions in which the body is misprogrammed to make more than it needs. They are referred to as familial hypercholesterolemias, and there is an informative page explaining these rare conditions at the National Institutes of Health (tinyurl.com/ld48). However, a more common condition is an unbalanced diet: too much fat and sugar and not enough grains, fiber, fresh fruits and vegetables. This can contribute to elevated blood cholesterol levels with especially high levels of the LDL (low-density lipoprotein) cholesterol associated with chronic disease. When there is stress, smoking, excess alcohol and lack of physical activity, things can get even worse.
DEAR DR. BLONZ: I filled out an online health questionnaire, which told me I had a "sluggish liver." Three of the items I had checked were cellulite, a hard time losing weight and frequent pains in the hips. The site recommended a particular dietary supplement that, of course, they were selling, which made me quite suspicious. What is known about sluggish liver? -- B.N., Janesville, Wisc.
DEAR B.N.: I have seen the term "sluggish liver" used to explain everything from hemorrhoids to headaches, but the entire concept of the "sluggish liver" has no real medical meaning. The liver is a very complex organ, perhaps the hardest working and most diverse organ in our body. Its responsibilities include: making blood and various blood proteins; detoxifying chemicals, including alcohol and all matter of drugs and contaminants, whether they are eaten, injected, absorbed through the skin or present in the air we breathe; manufacturing and storing glycogen, a form of stored glucose (blood sugar); manufacturing fats whenever the body has more dietary energy (calories) than needed at the moment; facilitating the burning of fats when there is insufficient energy; producing bile, a substance needed to digest fats; storing iron and other vitamins and minerals; and making many of the factors that help clot the blood.
The implication of such an impressive list is that there are serious consequences if the liver is not functioning up to par. But what does it mean if it is "sluggish"? It is just too vague a term. Using it is like telling a new doctor that you don't feel well and then expecting a complete diagnosis and treatment plan.
There might be nothing wrong with your liver, but if there was, it would not be something you could uncover through an online questionnaire. A health professional can take a careful history, do a physical examination and order any appropriate laboratory tests. For more background, see the NIH page on liver diseases is at: tinyurl.com/4p8kcv.
Send questions to: "On Nutrition," Ed Blonz, c/o Universal Uclick, 1130 Walnut St., Kansas City, MO, 64106. Send email inquiries to firstname.lastname@example.org. Due to the volume of mail, personal replies cannot be provided.