DEAR DR. BLONZ: I am hoping for your take on this "miracle ice hack" that says we lose body weight when we drink ice water, because the body has to use its calories to bring the water up to body temperature. I see this mentioned periodically, and it seems too good to be true, but some inescapable logic makes me curious. -- S.F., Chicago

DEAR S.F.: Wouldn't that be an easy fix? This "miracle ice hack" emerges periodically and sounds enticing enough to have many asking whether it makes sense. It is correct that the body would need to use its energy, measured in calories, to raise ice water -- or any cold food -- to body temperature.

However, a check of the math shows this to be insignificant regarding body weight. The mixup stems from the fact that calories used as a unit of heat in physics differ from the calories used to express the energy in food (and body fat) -- by a factor of 1,000.

In physics, a calorie is the unit of energy needed to raise the temperature of 1 gram of water by 1 degree Celsius. By contrast, the food/fat calorie is 1,000 times that amount, the energy needed to raise 1,000 grams of water (1 kilogram) 1 degree Celsius.

To help understand what "calorie" you are referring to, food/fat calories are spelled with an uppercase "C", but that never worked out well, especially if "calorie" is the first word of a sentence. Then there was the issue where mid-sentence "C"alories get inadvertently changed to lowercase by proofreaders. In scientific articles and published literature, food calories are written as kilocalories, or kcals. But these terms caused confusion. Nutrition and Supplement Facts labels do not use kilocalories or kcals. They capitalize the "C" in calories, although this distinction is not appreciated.

As a result, the calorie has been left on its own in the popular press, and we remain vulnerable to issues such as this "miracle ice hack," which has people wondering why ice water doesn't make them thin.

Here's the math to show how ice water fails to provide a chill way to lose weight. To avoid confusion, I will specify "thermal calories" for those that relate to one gram of water and kcals for those that relate to one kilogram of water (the latter being the food/body fat calories). Let's use the measure that there are 3,500 kcals in a pound of body fat (for reference, this is the equivalent of 3,500,000 thermal calories). Raising the temperature of 1 cup (8 ounces, or 227 grams) of ice water from refrigerator temperature (5 degrees C) to body temperature (37 degrees C) reflects a rise of 32 degrees (37 – 5 = 32 degrees change). The energy required for this rise is 7,264 thermal calories (227 grams x 32 thermal calories per degree); 7,264 thermal calories are equivalent to 7.3 kcals.

The chilling perspective here is that 8 ounces of ice water "burns" 7.3 kcals to bring it up to body temperature, and there are 3,500 kcals in a pound of body fat, so it would take 28 gallons of ice water to burn the energy equivalent of 1 pound of body fat.

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: Tell me more about Celtic sea salt, promoted all over social media for a number of health benefits. These include alkalizing the body, balancing blood sugar, eliminating mucus buildup and improving brain function (by remineralizing the blood-brain barrier), while providing benefits from over 80 minerals, including magnesium, potassium, calcium and iron. I wanted to check, as I think it's all a bit much for salt. -- S.F., San Diego

DEAR S.F.: Methinks it's a bit much as well. Such promotions contribute to the growing shaker of evidence that we must not base health decisions (or perhaps any decisions) solely on what we learn from social media. It is also vital to understand that because an advertisement mentions the presence of an essential nutrient does not mean it provides enough to have an effect. Always verify with objective information from experts academically trained to study the topic. Misinformation descends to risky business if applied to decisions about health.

The predominant substance in sea salt is sodium chloride. Given the amount used in a serving (one-quarter teaspoon), there wouldn't be enough other ingredients to affect an otherwise healthy body. The seawater used to make this salt may contain a variety of other minerals, but in minute amounts. Videos and promoters may mention mineral names and what they do, but that doesn't mean the salt gives you enough to make or enhance that action.

A food's Nutrition Facts label must declare its per-serving amounts of calories, fat (total, saturated and trans fats), cholesterol, sodium, carbohydrates, protein, vitamin D, potassium, iron and calcium. To claim something is a "good source" or stating that it "provides" or "contains" an essential nutrient, one serving needs to provide at least 10% of the Daily Value requirement; if claimed to be an "excellent" source, the serving must provide at least 20%. What besides sodium is on the Nutrition Facts label of Celtic sea salt? My read revealed one-quarter teaspoon provides 450 mg sodium and 0.4 mg iron (2% of iron's 18-milligram daily value). No other minerals are declared. What about calcium and magnesium? Yes, small amounts are found in seawater, but is insufficient to be declared on the label. Consumer protection agencies review product labels, and there are penalties for misrepresentations; such is not the case for social media.

Your question also mentions "alkalizing the body, balancing blood sugar, eliminating mucus buildup and improving brain function" by an effect on the blood-brain barrier -- I could find no evidence to support these, either. I have no problems with safe, sustainably harvested sea salt, but exorbitant promotional claims leave a bad taste. So, be wary, because such claims have spread like invasive weeds on social media.

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: What are your thoughts about farmed salmon, and how color additives are used to make it look like wild salmon? Do you have issues with farmed fish? -- M.C., Hayward, California

DEAR M.C.: The "you are what you eat" paradigm applies to fish as well as to humans. You may be surprised to learn that the genetically predetermined color of salmon is closer to gray. The characteristic "salmon pink" is a byproduct of their diet -- through their consumption of color compound-rich plants and algae, and also from eating smaller crustaceans or other fish that have eaten those colorful items. A key color compound is astaxanthin, a reddish antioxidant pigment in the carotenoid family. Interestingly, canthaxanthin, a compound related to astaxanthin, is used in tanning pills; when taken as a supplement, their color distributes in the fatty layer of the skin to provide the "tanning" effect (for more on tanning pills, check b.link/3rjug8).

Wild salmon get their color naturally, but farm-raised fish get it only if purposefully fed plants or animals containing the color-causing compounds, or if a color additive is added to their feed. Aside from individuals who might have a sensitivity or allergy to carotenoid compounds, there is no evidence of risk to consumers from astaxanthin when used as a "natural" color compound in fish feed. Check with your health professional if you have any concerns.

Regarding farmed fish in general, I lean toward wild-caught fish when available, but it's not a rigid preference. A wild fish caught in yucky waters offers no health advantage over fish raised in a sustainably managed fish farm.

I encourage consumers to speak with their fish suppliers to learn about the origins of the wild or farmed fish they are considering. Ideally, sellers should have this posted on the package or display case. This information should also be available from supermarket chains, but you may have to ask the manager. Always remember that you are the customer; let them know that if they want your business, they need to be upfront with such information. If you are given the name of a supplier, you can do your own research online to find out more.

It's great to find a fishmonger that does this type of screening for the customer as a matter of routine. This research also makes sense for your meat and poultry purchases. Your question relates to salmon, which is definitely a favorite in our house. We sometimes purchase wild salmon, but often go for sustainably farmed fish, such as that from Loch Duarte, a fish farm in Scotland (cleanfish.com). It's in our local market, but I encourage you to check at your local fish store for this or a similar line of sustainably raised fish, or you can encourage your store to carry one. Stores seek to offer what their customers prefer, but often you need let them know exactly what that is.

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.