DEAR DR. BLONZ: Is there any concern about the different forms of ascorbic acid in many vitamin C supplements, that some are not the best form for the body? I read that rose hips should be used for vitamin C. Is this correct? I have tried, without much luck, to find a chewable vitamin C supplement with rose hips as the source of vitamin C. Does it really matter? Thanks. -- S.T., Raleigh, North Carolina

DEAR S.T.: The design of marketing is to motivate customers to select their product over the competition's. Always be a consumer who checks things out. Rose hips are one of the richest natural sources of vitamin C. Because it is relatively costly, however, it is doubtful that you will find a vitamin C supplement that relies exclusively on rose hips. A careful read of labels will reveal that supplements claiming to be "rose hips vitamin C" are really vitamin C with a little bit of rose hips tossed in for good measure (and label appeal). The same goes for acerola cherries and Camu Camu, other rich natural sources of vitamin C. Besides, whether it comes from rose hips, acerola cherries, an orange or a laboratory, vitamin C is vitamin C, and it is all ascorbic acid.

One benefit of having a natural source for the vitamin C supplement, at least in theory, would be the non-vitamin nutrients and phytochemicals that are present with the naturally occurring vitamin. I qualified this with an "in theory" because you would need to check the label or manufacturer information to verify if any other desirable substance is present at a sufficient level to provide a benefit. Read more about vitamin C at b.link/r2nvm2g.

DEAR DR. BLONZ: I have had a leaded crystal decanter of very expensive Cognac on the shelf for many years. When taking it out at a party, a guest told me not to have more than a sip because lead crystals are dangerous to your health. I know that lead is dangerous, but wanted your opinion as to whether I need to dispose of this wonderful Cognac brandy. -- S.A., Dover, Delaware

DEAR S.A.: Consider this a cautionary note, especially where the fate of your world-class Cognac is concerned. But storage in a leaded crystal decanter will give rise to elevated concentrations of lead, and lead is most certainly dangerous to one's health. Safety dictates that one should not store liquids in leaded crystal glasses or bottles, or drink from such liquids on a daily basis (this would especially be the case if one is pregnant).

Finally, don't feed an infant or child from a leaded crystal baby bottle or cup. The decision of whether to dispose of your Cognac is yours. The body is capable of eliminating lead, but unfortunately, this process is slow. Lead poisoning occurs when the rate of intake exceeds the rate of removal. When drinking a liquid stored in leaded glass, you get a dose of lead with every sip. The longer a liquid sits in a leaded glass, the greater the amount of lead that can leech into the liquid. The alcohol in Cognac, along with the fact that it is slightly acidic, speeds up this process. The increased cut-glass surface area of those classic containers exacerbates all this. How much lead your body can tolerate is a discussion you should have with your physician. Consider buying a lead test kit -- good to have one in the house. For more on lead poisoning, see b.link/cq39597.

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 limiting foods with added simple carbs in my diet, but I am concerned after learning that maltodextrin is all over and considered the worst kind of carbohydrate. I checked and found various sources with opposing views, and I wanted more information on this aspect. -- B.P., Tulsa, Oklahoma

DEAR B.P.: Unless there is a specific health reason, you don't have to panic about every gram of carbohydrate. (The stress of the worry may do you more harm than the carb!) The goal is to work toward a whole-foods diet foundation and healthy lifestyle; this effectively blunts risks associated with less-than-healthful foods that we should be free to enjoy on occasion.

On a related note (for this question and the next), in recent years it has become common to find a glut of advice on food and health topics. Consider this an effect of social media, where a science education is not required to post. One only needs the motivation to present like an "expert." Where significant numbers of followers translate to compensation, many self-promote by complimenting their own "wisdom" using different names from secondary accounts they have created. This has turned social media into a "Who Do You Trust?" situation (this was the name of a television show from my childhood). The message here is always to seek confirmation based on actual evidence from those having advanced academic training in that field.

DEAR DR. BLONZ: I am involved in a debate over the most anti-inflammatory, healthful food, and I opted for blueberries, whereas others in the group suggested other possibilities. Is there such a food out there, or any that has earned this label? -- A.W., Phoenix, Arizona

DEAR A.W.: I am sure there are promoters willing to put their food or product on such a list, but I refuse to participate. The idea that we need to label or seek the No. 1 most anti-inflammatory health food (or supplement) is utter nonsense. The goal is to have an overall healthy diet chock-full of healthy foods, rather than feeling the need to seek one that you are told will make things better. Health doesn't work that way. Think of diet like a concert, with the totality of our selections making the music. We all need to stay in tune with our bodies and the twists and turns life throws our way.

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: My regular enjoyment of cashews was put at risk when I heard someone say at a party that they never ate them since they learned cashews contain a toxin and must be avoided. I was skeptical, as I could not imagine their wide acceptance if this were the case, but it did give me pause. I was hoping that you could respond. -- S.N., Los Angeles, California

DEAR S.N.: As someone who enjoys cashews and other nuts and seeds daily, I share your skepticism of those comments. To provide some clarity, cashews belong to the same family that includes the itch-provoking three: poison oak, ivy and sumac. The poison readily shared by those three is the compound named urushiol. (For more on this irritant, see b.link/b2xb6d6.)

The confusion likely stems from the fact that cashews grow with protective shells (see b.link/rf45kfvv), and it's those shells -- not the nuts we enjoy -- that can contain some urushiol. There is careful separation, followed by roasting or steaming, that eliminates the urushiol risk.

It's not only cashews. The outer hull of pistachios -- again, not the shells or kernels inside -- can also contain trace amounts of urushiol; that protective cover also being removed before the shell is roasted and the kernel lands in our hands. Finally, there is a relatively small amount of urushiol in mangos, but it is in the skin, sap and leaves, not the flesh we eat. However, those who have become hypersensitive to urushiol should be aware when handling mangos.

Consider urushiol a particularly annoying example in nature's vast array of protectants designed to keep poachers away so that the plant's seeds have time to mature and develop into plants of their own.

DEAR DR. BLONZ: I've recently become more aware of the nutrition content of food products, and I am concerned about potassium, having learned that too much is as bad as too little. Why isn't potassium listed on most food labels? -- G.B., via email

DEAR G.B.: Potassium, with the chemical symbol K, is a key electrolyte in the body, along with sodium, chloride, calcium, magnesium and bicarbonate. Among potassium's key actions is the regulation of water balance inside our cells. (Contrast this with sodium, which regulates water balance outside the cells.) Potassium is also involved in maintaining our body's acid-base balance and in the transmission of nerve signals, which makes it key to such activities as keeping our hearts beating.

You want to avoid having too much potassium, and supplementation is not usually needed unless there is a specific health problem or a medication in use that might deplete the body of this mineral. If the kidneys are working normally, excess potassium will be excreted in the urine. The adult daily value for potassium is 4,700 milligrams per day. Potassium per serving can be listed on a food label, but it is not required. Good food sources for potassium include fresh, whole foods such as apricots, lentils, acorn squash, potatoes, bananas, legumes, citrus fruit and avocados.

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.