DEAR DR. BLONZ: Thank you for the column on muscles in the aging body. As a trainer who works with many as they age, I've found that most don't realize adults can lose about 5% of their muscle mass every year. The more muscles you have, the higher your metabolic rate. As highlighted in the attached article, adults can lose 3% to 5% of their muscles per decade, with this rate accelerating after 60. This is a natural process referred to as sarcopenia. The decline, as you mentioned, can be slowed and even reversed with regular resistance training. It is important to take the time to find a reliable trainer and lift weights. -- D.B., Del Mar, California

DEAR D.B.: I appreciate the comments and compliment your career focus on helping clients in this important area of life and health. Fitness and an active lifestyle remain one of life's best returns on investment. Keep it as a lifelong relationship rather than turning to it only after an illness, injury, surgery or when you realize you are no longer able to keep up with your peers.

Take it easy when you start, especially if there are problem areas or medical issues to consider. If you are a senior who has been inactive for a while, be sure to check in with your primary care physician before beginning any training program. Fitness is a worthy goal, but the last thing you want to do is rush things. To avoid overloads or other problems, seek the advice of a trainer who is experienced in working with seniors and who has successfully dealt with your issues.

Consider taking a complete set of body measurements and noting your clothing sizes before you start. Your clothes may begin to fit differently over time. Hunger may increase with your activity level, but seek to satisfy hunger with fruits and other low-calorie, whole foods, all eaten slowly with good hydration. Keep track of your weight weekly, but be less concerned with the number and more comforted by working toward the benefits of a more active lifestyle.

DEAR DR. BLONZ: I am looking to get certified in fitness and nutrition. If you know any home study courses, websites, or anyone I can call it would be very helpful. Thank you in advance for your help. -- A.C., Charlotte, North Carolina

DEAR A.C.: I see this a lot -- especially on social media -- and advise caution when dealing with certificate-granting organizations. Do some in-depth checking on any organization that grants fitness or nutrition certificates. Do scientists and academics in the field recognize such credentials as legitimate? Is the certificate-granting faculty trained with bona fide academic degrees -- not ones granted by a similar certificate-granting organization? Don't be overly swayed by the fact that an organization claims to be accredited. Outfits can form their own "independent" organizations and accredit themselves! Be wary, or you may end up with nothing more than a worthless piece of paper.

It is difficult to gain a real knowledge of nutrition via a certification/mail-order course. Nutrition is a science based on biochemistry and complex physiological concepts, and traditional colleges and universities require years to teach the basic tenets of these sciences. Consider taking community college or university extension courses in fitness/nutrition to learn more about the field you want to pursue.

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: 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.