Arguably, given his national stage and reach, Dr. Oz is one of the biggest pill pushers in the United States. In the seven months I’ve been watching his show, I cannot remember a week going by without him promoting one dietary supplement or another.
Oz then made one of the zaniest recommendations I have ever heard him make. To quote his site,
I was actually on my elliptical while watching the show and I almost dropped my cellphone on which I was taking notes when he uttered his words on zinc. “What???” I thought to myself. “Is that true? Does Zinc elevate leptin? Does elevating leptin actually reduce weight? Is there any science to support any of these assertions?”
Now leptin, discovered in 1994 by studying obese mice, is a known hormone produced by our bodies that acts as an appetite suppressant by suppressing neuropeptide Y, a known appetite stimulant that then suppresses another stimulant and continues down a full cascade (too complicated for this blog). At one point, leptin held promise as a means to reduce weight, but suffice it to say that numerous studies have failed to support the conclusion that increasing leptin reduces weight.
Notwithstanding, Dr. Oz took it one step further. He was actually recommending that taking surplus zinc would somehow raise the body’s leptin levels and help one lose weight. I knew at that point that I had a major research project ahead of me to research the facts and discover the truth. After seven hours of research, I discovered what I believe to be the facts.
Before I discuss the leptin-zinc connection, let’s first review of role of zinc in our health.
Here was one of them.
Effect of Zinc Supplementation on Serum Leptin Levels and Insulin Resistance of Obese Women
by Dilina Do Nascimento Marreiro, Bruno Geloneze, Marcos A Tambascia, Antonio C Lerário, Alfredo Halpern, Silvia Maria Franciscato Cozzolino
by Elizabeth S. Ott and Neil F. Shay
by Konukoglu D, Turhan MS, Ercan M., Serin O.
by Ming-Der Chen, Yuh-Min Song, Pi-Yao Lin
In the Chen study, data from animal research supports the existence of the zinc-leptin link. Ming-Der Chen, Ph.D., and colleagues reported in a March 2000 article published in "Hormone and Metabolic Research" that leptin levels increased when a moderate dose of zinc was fed to mice with experimentally induced diabetes. Interestingly, both zinc deficiency and high-dose zinc suppressed leptin production. Now although this was also only an animal study, that last sentence should make you wince. Dr. Oz is recommending that the average person who wants to lose weight should supplement with 12 to 15 mg of additional zinc when it may, in fact, be associated with the opposite intended effect.
by Susan B. Roberts, Ph.D., et al.
So here’s the only logical conclusion one can reach, as Dr. Oz likes to say, “in case you missed it,” taking zinc to increase your leptin levels in the absence of a zinc deficiency has no expected benefits and potential harmful side effects.
|0–6 months||2 mg*||2 mg*|
|7–12 months||3 mg||3 mg|
|1–3 years||3 mg||3 mg|
|4–8 years||5 mg||5 mg|
|9–13 years||8 mg||8 mg|
|14–18 years||11 mg||9 mg||12 mg||13 mg|
|19+ years||11 mg||8 mg||11 mg||12 mg|
Sources of ZincFood
A wide variety of foods contain zinc (Table 2). Oysters contain more zinc per serving than any other food, but red meat and poultry provide the majority of zinc in the American diet. Other good food sources include beans, nuts, certain types of seafood (such as crab and lobster), whole grains, fortified breakfast cereals, and dairy products.
Phytates—which are present in whole-grain breads, cereals, legumes, and other foods—bind zinc and inhibit its absorption. Thus, the bioavailability of zinc from grains and plant foods is lower than that from animal foods, although many grain- and plant-based foods are still good sources of zinc.
|Oysters, cooked, breaded and fried, 3 ounces||74.0||493|
|Beef chuck roast, braised, 3 ounces||7.0||47|
|Crab, Alaska king, cooked, 3 ounces||6.5||43|
|Beef patty, broiled, 3 ounces||5.3||35|
|Breakfast cereal, fortified with 25% of the DV for zinc, ¾ cup serving||3.8||25|
|Lobster, cooked, 3 ounces||3.4||23|
|Pork chop, loin, cooked, 3 ounces||2.9||19|
|Baked beans, canned, plain or vegetarian, ½ cup||2.9||19|
|Chicken, dark meat, cooked, 3 ounces||2.4||16|
|Yogurt, fruit, low fat, 8 ounces||1.7||11|
|Cashews, dry roasted, 1 ounce||1.6||11|
|Chickpeas, cooked, ½ cup||1.3||9|
|Cheese, Swiss, 1 ounce||1.2||8|
|Oatmeal, instant, plain, prepared with water, 1 packet||1.1||7|
|Milk, low-fat or non fat, 1 cup||1.0||7|
|Almonds, dry roasted, 1 ounce||0.9||6|
|Kidney beans, cooked, ½ cup||0.9||6|
|Chicken breast, roasted, skin removed, ½ breast||0.9||6|
|Cheese, cheddar or mozzarella, 1 ounce||0.9||6|
|Peas, green, frozen, cooked, ½ cup||0.5||3|
|Flounder or sole, cooked, 3 ounces||0.3||2|
The U.S. Department of Agriculture's Nutrient Database Web site lists the nutrient content of many foods and provides a comprehensive list of foods containing zinc.
If you read this far, you deserve this cute video about Zinc. Just copy and paste in your browser, and enjoy!