DEAR DR. BLONZ: Can dietary supplements help with alcohol hangovers? The one I am considering states an ability to bind the toxin acetaldehyde, and I recall it is involved. It says it works on all alcoholic beverages. Could you explain what this is and whether there is any reason to believe that a product like this might work? -- B.S., San Diego, California

DEAR B.S.: A toxin is any substance that can damage systems, organs and cells. Fitting that description are alcohol (ethanol) and acetaldehyde, alcohol's intermediate breakdown product. Most nutrients we eat get absorbed after they've been digested into smaller parts. This involves actions by enzymes and digestive juices, as well as the physical actions of the stomach, small intestine and large intestine. Alcohol is one of the few substances that can be absorbed directly through the lining of the stomach. This explains why we tend to feel its effects sooner, especially when consumed on an empty stomach.

The body has tolerances for alcohol intake due to the limited capacity of the liver, the organ that metabolizes (breaks down) alcohol. The enzymes in the liver can metabolize approximately one drink per hour. (More on alcohol at b.link/qvbn8h.) When consumed at a more rapid rate, alcohol and acetaldehyde get put in the queue awaiting breakdown and elimination. The "queue" here refers to all body fluids, including blood and body tissues. As the concentration of alcohol metabolites increases, we experience intoxication and alcohol's other negative effects.

Tolerance to alcohol correlates with body size. This is not so much because larger individuals metabolize alcohol faster. Rather, it's because they have a greater volume of body fluids and, thus, a larger holding volume to dilute alcohol and its metabolites before processing. Larger people may not "feel it" to the same degree as smaller individuals. This can enable greater intakes and allow alcohol's toxins to unleash their effects for longer periods of time.

Interestingly, metabolic differences have been shown between Asians (and some Native Americans with Asian ancestry) and Caucasians. Approximately 50% of Asians have lower levels of the aldehyde-processing enzymes. With them, ethanol is converted to acetaldehyde, but the process then stalls, allowing an accumulation of alcohol byproducts that can cause adverse reactions, such as increased heart rate and facial flushing. No surprise that abstinence or moderation are underlying messages for any affected in this way.

Acetaldehyde, that first breakdown product, is actually more toxic. A product that binds acetaldehyde could be beneficial. But acetaldehyde is formed primarily by the liver inside the body, not in the digestive system, where this product acts. The product has nothing to offer there.

One potential minor effect might be an ability to bind congeners, impurities in certain alcoholic beverages that can make hangovers more likely and more intense. Beverages with the highest levels of congeners include bourbon, brandy, whiskey, dark rum, dark beer and red wine. The lowest levels of congeners are in vodka, gin, light rum, lager and pilsner beer, and white wine. If it works at all, this product may only affect hangovers caused by congeners, but you should demand objective evidence.

Finally, dehydration, when the body lacks sufficient water to function normally, can also contribute to hangovers. That said, the water consumed with this supplement may be more likely to have a beneficial effect than the pills themselves. (More on hangovers at b.link/3gaup5k.)

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: At a holiday dinner party, the host and their friends began talking about a line of health products they sell. I hadn't understood this was the theme of the night, and I remain the only holdout. The main product is an anti-aging stem cell product. A doctor heads the company, and there are many testimonials, and those friends are making a bit of money. Below are links to the site. Do you have any policies or recommendations? -- B.B., San Diego, California

DEAR B.B.: I commend your well-founded skepticism. It's difficult for a trained professional, let alone the public, to keep up to date with all the dubious health-related product-promoting schemes that now pervade social media. I checked out the links (not included here) with all their promises and found nary a hint of clinical evidence to back them up. There's also limited information on the products' ingredients.

The individual in charge goes by "Doctor," but it never reveals what type of doctor. It says he is a leading, internationally known nutrition authority. Questions that come to mind include, "known by whom?" and "Where is he leading people?" There are ways to buy "Ph.D" credentials online with no classroom attendance required. They give credit for "life experience," but the main qualification is a willingness to pay. I recall when an academic colleague was able purchase a graduate degree for his dog!

Your party used a multi-level marketing (MLM) technique, often called a pyramid scheme. This marketing technique combines online elements with neighbor-to-neighbor selling, often seeking to recruit individuals onto their team (where the team leader profits from all sales). I've found that when health-related products are offered with promises of cures and profits, any demand for proof of efficacy takes a back seat. MLM plans typically involve the use of testimonials as evidence. Pitches follow the line that "it worked for them, so why not for you?" Add a pseudo-credentialed "Dr." and social pressures, and you end up with impressive marketing clout. For more on MLM, see b.link/x3t8mcd.

It's deceitful to claim expertise without training. And when the practice involves a health-related area, it can be dangerous. There is no effective way to purge all fraudulent practitioners from health care -- and AI has added a level of complexity -- so it falls upon us to remain vigilant. Resisting what is portrayed as a financially successful venture may not win you a popularity contest, but, absent objective evidence of efficacy, it remains the right thing to do.

Finally, always remember that quick fixes rarely work in the long term. They tend to raise your hopes and lower your bank balance, while creating the risk of unknown side effects and interactions with other products you're taking, or with existing health conditions and medications you're using. There is also the more insidious element that a treatable ailment progresses to a more advanced stage while untested products are given their try. For more on health fraud, see the article at b.link/7kwp2hx.

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 want to lose weight without a prescription drug. I am seeking information on fat-burning foods or supplements that are promoted for a claimed ability to help weight loss by making the body burn fat while you sleep. What about caffeine and herbal stimulants (not taken at night, of course)? Thank you in advance for your help. -- G.E., Raleigh, North Carolina

DEAR G.E.: There is no evidence of a meaningful increase in fat loss during sleep from adding specific foods. The "fat-burning food" label is mostly nonsense. Diet and sleep do interact, but the main levers are when and how much you eat, not magic nighttime foods.

Fat is metabolized (burned) as part of normal energy metabolism. To burn more, we must expend more energy, for example, through exercise and other forms of muscular work.

It is best to avoid turning to "stimulant" supplements, such as caffeine or guarana, for weight loss. The body needs rest to repair, regenerate and clear metabolic waste. It produces substances that promote rest when this is the case. The key calming substance is adenosine. Receptors on cell membranes respond to adenosine's presence by activating our metabolic brakes. Caffeine can bind to adenosine receptors and prevent the slowdown. While caffeine is thought of as a stimulant, it does not stimulate so much as it blocks the action of receptors that slow things down.

A reasonable intervention for weight loss without drugs is healthy eating combined with regular physical activity. Exercise not only burns calories, but it can also increase muscle mass, which has the added benefit of making the body burn more calories than other tissues, even at rest.

Regarding sleep, we all lose weight while resting. The only time we are not losing is when we are eating and drinking. The longest "fast" of the day is -- you guessed it -- when we are asleep! (Also, that's why the morning meal is named "breakfast" -- we "break" the "fast.") The idea, however, that a supplement will help you to drop a few sizes while you slumber is pure folly. For more on herbal remedies and weight loss supplements, see b.link/4vdmugu.

DEAR DR. BLONZ: What controls how much cholesterol the body manufactures? Can it make more cholesterol than it gets from food? -- E.D., Ames, Iowa

DEAR E.D.: Cholesterol is an essential structural component of every cell in the body. Even if there was no cholesterol in your diet, your body would have to make it. In addition, cholesterol is a precursor for several hormones, including estrogen and testosterone. Most of the cholesterol is manufactured in the liver. When cholesterol is present in the foods we eat, the liver is programmed to make less. There are several genetic conditions in which the body produces more cholesterol than it needs. Referred to as familial hypercholesterolemia, they tend to be rare (for more on this see b.link/smgfxsp).

More common, however, is the condition in which the body receives an unbalanced diet that's heavy on the carbs and processed foods and light on the whole food fresh fruits, vegetables and high-fiber grains. This results in blood cholesterol levels that are way out of whack. For more on using diet to lower cholesterol, see b.link/ypvky3a.

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.