DEAR DR. BLONZ: I have questions about caffeine and alcohol and their effects on hydration. A blog explained that caffeinated beverages are diuretics, and that when you drink 8 ounces of a caffeinated beverage such as tea, coffee or soda, your body will lose 12 ounces of water. That would mean that these beverages are dehydrating instead of hydrating. It made little sense to me, but this was written by people described as experts. Where does alcohol rank as a diuretic? -- M.S., Hayward, California

DEAR M.S.: A word about “experts” on blogs, podcasts or whatever: Have filters in place when you encounter “expert” as a descriptive. Keep the information they offer “on hold” until you are confident of their training and ability to demonstrate an objective, evidence-based foundation for their statements. There are a variety of unaccredited “pay-to-play” organizations selling what appear to be legitimate advanced degrees or proclamations of “board-certified” expertise. Some of these dubious credentials require nothing more than a hefty check, with perhaps a few online courses. Not really what you would assume from one claiming expertise. Some posers are great salespeople -- another red flag being when messages are associated with products being sold.

Diuretics are substances that increase urine output. By this definition, even water could be considered a diuretic. Caffeine is considered to have a mild diuretic effect, but caffeinated beverages such as those you cite would not draw more water out of the body than they contribute. If, however, you were to take caffeine as an over-the-counter or dietary supplement product, it makes sense to be well-hydrated before you start.

The National Academies of Science’s Health and Medicine Division has established a Daily Reference Intake (DRI) for water. The guidelines state that adequate hydration is a daily intake of 2.7 liters (91 ounces) of water for women over the age of 19, and 3.7 liters (125 ounces) for men. Those who are active or live in hot climates may need to consume more. About 80 percent of this total would come from drinking water and other beverages, including caffeinated beverages. The rest comes from food. Vegetables and fruits, for example, are mostly water by weight.

Alcohol also has a mild diuretic effect, but it works differently. One of its effects is to inhibit the release of anti-diuretic hormone (ADH), a hormone that limits the amount of urine produced in the body. When alcohol is around, less ADH is released, which translates to more urine leaving the body. The effects are present in about 20 minutes, which any beer drinker is likely to affirm.

Alcohol’s diuretic effects play an interesting role, and many of alcohol’s effects depend on the blood concentration of its metabolites. The body has a rate at which it processes alcohol, and it uses its fluids as a storage queue for metabolic byproducts awaiting processing and elimination. As such, alcohol’s diuretic effect enhances the consequences of over-consumption.

Tolerance to alcohol is said to be weight-related: The larger you are, the more you can tolerate. This is not so much because larger individuals metabolize alcohol faster, but because a larger body has a greater blood volume to begin with.

Send questions to: “On Nutrition,” Ed Blonz, c/o Andrews McMeel Syndication, 1130 Walnut St., Kansas City, MO, 64106. Send email inquiries to questions@blonz.com. Due to the volume of mail, personal replies cannot be provided.

DEAR DR. BLONZ: This is in response to your column about a soccer game, the provision of a sugary sports drink for children, and your concerns about active children having a drink with higher sugar content. Some years ago, a soccer coach sent me a study in the journal Pediatrics that discussed the best type of drink. Based on that study, a good choice would be a drink like Gatorade. I just went to my fridge and confirmed what I thought: Gatorade has 14 grams of sugar (50 calories) and 110 mg of sodium in an 8-ounce serving. This is exactly what that paper reported. It led me to believe this would be the ultimate drink for the children in this case, and would also have the benefit of saving 10 calories per serving, compared to the higher-sugar drink. -- F.S., Tempe, Arizona

DEAR F.S.: A sports drink can be helpful for those involved with hour-plus workouts or athletic events; this would especially be the case when exercising in warm and humid climates, or for any individual who tends to perspire heavily. Water is the key, but a properly formulated drink can help replace the sodium and potassium lost through perspiration. A small amount of carbohydrate sweetener helps make the drink more palatable, and it provides a small boost of the type of fuel that is in short supply during an extended workout -- especially one that requires periodic bursts of energy. You don’t want too much sugar, as that can work at cross-purposes by slowing nutrient absorption. I also advise against giving exercising children any drinks that contain stimulants, such as caffeine.

The article in the journal Pediatrics (tinyurl.com/ybxaf49z) describes a beverage where an 8-ounce serving contained 14 grams of sugar and 110 milligrams of sodium. This is the same formula found in Gatorade and some other sport drinks. Check the Nutrition Facts label on the products before you buy.

I encourage readers to make their own sports drinks from fresh juices (tinyurl.com/krkj8mx). Such a beverage not only provides the same water and electrolytes, but you get the bonuses of genuine flavors and the additional nutrients and phytochemicals in the fruit juice. Having young athletes involved with real-food functional recipes is also a great lesson to complement their workout. To date, I have made this drink using lemons and limes that grow on our property, but also from Concord grape, pomegranate and cherry juices. Any homemade sports drink is a perishable food, so keep it cool or frozen.

Send questions to: “On Nutrition,” Ed Blonz, c/o Andrews McMeel Syndication, 1130 Walnut St., Kansas City, MO, 64106. Send email inquiries to questions@blonz.com. Due to the volume of mail, personal replies cannot be provided.

DEAR DR. BLONZ: I am 59 with no family history of diabetes, but was recently diagnosed as having Type 2. I know I have to lose some weight, but am curious about other steps to take. I read your bio online at blonz.com, and it states that you did some research on insulin and obesity. What exactly did you research, and what advice do you have about diabetes? -- F.S., Charlotte, North Carolina

DEAR F.S.: My doctoral research focused on the role of insulin in the development of obesity. I used an animal model that was genetically tweaked to get obese if fed a normal diet. As adults, these animals had an elevated insulin level (hyperinsulinemia) in addition to their obesity; I found that in this specialized animal model, the excess insulin preceded the obesity. Such research helps us better understand the relationships between obesity and insulin, and, by extension, diabetes -- but it won’t help us much in dealing with your particular situation.

During digestion, dietary carbohydrates tend to be broken down into their glucose building blocks. The glucose is then actively absorbed into the blood, at which point it is often referred to as “blood sugar.” Glucose, a key source of energy for the body, travels throughout the body via the blood. To release its energy, however, glucose needs to get into the cells where the work is done, and for this it requires insulin: the hormone produced and released by the pancreas as the blood glucose level rises. Once inside the cells, glucose can be used to provide energy for work, such as muscular efforts or cellular repair. When there is sufficient energy, the glucose gets changed into fat, the body’s most concentrated form of energy. It then gets put away in storage in the body’s fat cells.

Diabetes is present when there’s insufficient insulin to get excess glucose out of the blood and into the cells. Type 1 diabetes is when the pancreas is unable to produce the insulin. In such cases, replacement insulin needs to be provided from an external source, usually via injection. Insulin, a protein, can’t be taken orally because the digestive system would break it down before it could be absorbed. More common is Type 2 diabetes; this occurs when the pancreas is still able to produce and release insulin, but it’s unable to keep up with the demand, and the blood glucose level remains elevated. Treatments in such cases can include diet and lifestyle adjustments, or medications to stimulate the pancreas to release more insulin. Type 2 diabetes used to be known as “adult onset” diabetes because it was only seen in adults; not so anymore.

With weight gain, the fat cells increase in size, and enlarging fat cells are associated with a decreasing sensitivity to insulin. This “insulin resistance” means that the body needs more insulin to clear the same amount of glucose out of the blood. Obesity, in essence, overworks the pancreas, which is eventually unable to keep up. Between 80 and 90 percent of those with Type 2 diabetes are obese. This also helps explain why those with Type 2 diabetes often experience dramatic improvements when they lose a few excess pounds.

As there can be short- and long-term complications when one’s blood glucose remains elevated, the bottom line with any diabetic condition is to keep glucose within normal limits. Your task will be to get this done using diet, exercise, medications and/or insulin injections. I encourage you to speak with your family physician and a registered dietitian (R.D.). They can help you with mapping out strategies for weight loss and food selection. There is also a library of information at the American Diabetes Association (diabetes.org).

Send questions to: “On Nutrition,” Ed Blonz, c/o Andrews McMeel Syndication, 1130 Walnut St., Kansas City, MO, 64106. Send email inquiries to questions@blonz.com. Due to the volume of mail, personal replies cannot be provided.