DEAR DR. BLONZ: What controls the amount of cholesterol the body manufactures? Can it make more cholesterol than it gets from food? -- D.D., Sun City, Arizona
DEAR D.D.: Cholesterol is an essential structural element in every cell of the body. In addition, it serves as a base material for the body's manufacture of a number of hormones, including estrogen and testosterone. Most of the cholesterol in the body is manufactured in the liver. If there wasn't any cholesterol in your diet, your body would have to make some. When cholesterol is present in the foods we eat, the liver is programmed to make less.
There are a number of rare genetic conditions in which the body makes more cholesterol than it needs. More common, however, is an unbalanced diet that's heavy on fats and carbohydrates and light on whole foods like greens, grains and fruits. Add to this a stress-filled, unhealthy lifestyle, and you end up with blood cholesterol levels that are not ideal.
DEAR DR. BLONZ: Is it true that the body can maintain itself better with a more alkaline diet? Can a pH test of saliva be an accurate determination of the body's acid/alkaline levels? -- G.W., San Francisco
DEAR G.W.: Degrees of acidity or alkalinity are expressed in terms of their pH. Distilled water has a pH of 7.0 and is considered neutral. When the pH is higher than 7.0, the substance is a base (i.e., alkaline), and when the value is lower, the substance is an acid. The greater the numerical distance from 7.0, the stronger the acid or base. Coffee is considered weakly acidic with its pH of 5.0, but battery acid, a strong acid, has a pH of 0.8.
The pH of the human body is slightly alkaline and it is kept within a very narrow range: between 7.35 and 7.45. There are overlapping systems set up to maintain the correct pH because essential chemical reactions won't take place if the pH is out of whack.
The pH of food varies (for examples, see tinyurl.com/lfdmusr). The human body is adept at dealing with variances; it makes its adjustments while foods are in the digestive system, and also after they are absorbed. The kidneys play a key role: The pH of urine will change according to our state of health and/or disease, and it reacts to what we eat, drink or do. In addition to urine, our perspiration and breath also help to keep the body's pH in its optimal range.
Relying on a saliva pH test is of questionable value as a general diagnostic, or as an indicator of your body's pH. Our salivary pH varies, being affected by ongoing dental issues as well as by the flora that live in the mouth. Certain disease states, anxieties and medications can also influence pH. The systems in our body are designed to compensate to keep things on track. Healthful, whole foods from plants tend to be more alkaline, but we don't need these foods just for their alkaline nature: They are assets to health because they provide nutrients and naturally occurring phytochemicals honed by nature over the millennia to support the vitality of the plant. We do best with an assortment of healthful foods coupled with an active and limited-stress lifestyle.
Send questions to: "On Nutrition," Ed Blonz, c/o Universal Uclick, 1130 Walnut St., Kansas City, MO, 64106. Send email inquiries to email@example.com. Due to the volume of mail, personal replies cannot be provided.