Optimal Nutrition

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Do "fat burners" really work?

Dear Burning to know,

As you probably know, if you walk into any pharmacy or supplement shop, you will see dozens of products promising to make excess body fat melt away. Although manufacturers are not permitted to make these claims on the bottle, they run alluring ads in magazines and on TV. So, how are you to know whether or not the ingredients are safe and effective?

Weight loss supplements may work in three ways: one is by helping the body to break down body fat. The second action of weight loss supplements is to suppress appetite, which is a complex process. The human body's instinct is to survive, and once appetite suppressants are stopped, people become hungry. The third way weight loss supplements may work is by inhibiting the body from absorbing fat during digestion. Fat blockers don't work if a person isn't eating fat in his or her diet. They also won't prevent weight gain if a person is overeating protein or carbohydrates. Often, weight loss supplements contain more than one substance to generate weight loss from more than one angle. The ingredients are available alone, or with other substances. The following is a partial listing of some of the weight loss supplements you may see:

Carnitine
Promoted as a fat burner, carnitine naturally occurs in the body, and people can obtain it through eating meat, fish, poultry, and some dairy foods. Carnitine helps transport fatty acids to the muscle. In theory, it makes sense that more of it would help people get more fatty acids into the muscles, burning additional fat. Unfortunately, it doesn't live up to expectations, because taking its supplemental form doesn't result in increased fat burning.

Chromium Picolinate
Although this mineral helps metabolize carbohydrates and fats, it has not lived up to claims of increasing lean body mass and decreasing fat. As a matter of fact, the majority of the research done on this supplement shows it is not effective as a weight loss supplement. Some research showed damage to DNA with excess chromium picolinate that is exacerbated with Vitamin C. Taking in more than the body requires can actually reduce the binding capacity of iron in the blood, potentially resulting in iron deficiency and decreased ability to carry oxygen in the blood. This could negatively impact one's ability to exercise and expend calories.

Ephedrine
This acts like a hormone the body makes — norepinephrine. The action of this substance is associated with increased fat release from adipose (or fat) tissue, increasing free fatty acids in the bloodstream. Also increased are heart rate, heart contractility, body heat production, and metabolic rate. Ephedrine may also be able to suppress hunger. It has been shown that ephedrine is even more effective when combined with caffeine — but so are the side effects, including tremors, dizziness, insomnia, heart arrhythmias, headaches, and increased blood pressure. Due to these risks, the U.S. Food and Drug Administration (FDA) banned the sale of dietary supplements containing ephedra in 2004.

When a supplement touts "proven in clinical trials," it's time to dig deeper. That "trial" may have been performed on animals, or with amounts of the supplement not available for sale. The FDA does not closely monitor supplements, so there's no guarantee you're getting the ingredients you're paying for, nor any guarantee you're not getting some additional ingredients not listed on the label.

Once again, there is really no safe short cut or quick fix to losing weight, no matter how slick the ads! To lose weight and burn fat, you need to burn more calories than you consume. And fat burners, despite the hype, do not work as advertised.

Alice

Time-release dietary supplements

Dear Reader,

It's easy to become confused with the whole array of dietary supplements on the shelves nowadays. One form may claim superiority in advertisements, but how are you to know for sure which ones are right for you?

First of all, vitamins and minerals are needed in our bodies in relatively small amounts. Vitamins may be present in our blood, organs, or other tissues. Although each micronutrient (scientific term for vitamins and minerals) has a specific function, here's a brief overview by category:

  • Water-soluble vitamins (all the B vitamins and vitamin C) and many minerals act as co-enzymes, meaning they aid in chemical reactions in the body. Excessive amounts don't make reactions occur faster or more efficiently than adequate or recommended amounts. Plus, too much of one mineral may actually inhibit the absorption and effectiveness of another.
  • Fat-soluble vitamins (vitamins A, D, E, and K) are involved in specific roles of maintenance and repair of body cells and tissues. Unlike water-soluble vitamins, extra amounts of fat-soluble vitamins are not excreted, so over-saturation of these may lead to toxicity.
  • Minerals have a variety of functions, ranging from water and acid-base balance, to bone structure and co-enzyme activity, as mentioned before.

As long as you consume a sufficient vitamins and minerals, a constant influx is not necessary, and may also be harmful. For example, time-release niacin is not recommended because it can cause liver damage. Time-release iron supplements are ineffective because the point of release in the intestinal tract does not absorb this mineral efficiently. Some time-release supplements contain coatings that prevent the absorption of fat-soluble vitamins. As you can see, time-release nutritionals are certainly not worth the extra money manufacturers often charge for them. Besides, Mother Nature has already provided us with a way to time-release our nutrients... by getting them from a variety of foods, eaten at various times throughout the day.

To get to your last question, you are among quite a number of men and women who have expressed concern over whether their multi-vitamin "works" or "doesn't work"; that is not really the point of these supplements. Their purpose is to help certain people fill in nutritional gaps when they are unable to eat enough food or obtain adequate vitamins and minerals from their diet. Multi-vitamins also might be recommended for some vegetarians, dieters, and others who have food allergies, intolerances, or other problems associated with eating particular foods. A supplement may benefit the elderly, too, because sometimes older people can't absorb nutrients as well as they did in their youth. Remember, the meaning of a dietary supplement is to add to a diet, not to take the place of food!

Alice

Where can I find easy vegetarian recipes?

Dear Reader,

Having some vegetarian (or vegan or gluten-free) recipes on hand can be helpful, whether or not you're a vegetarian yourself. There may be times when you have company over who are vegetarian, for cultural, religious, or other reasons, and you want to be prepared. In addition, people may choose to consume fewer animal foods and products in their eating plans, and desire to find suitable and tasty meat-less substitutes. Vegetarian eats are not the bland, boring fare some may traditionally consider (plain tofu, boiled carrots, or alfalfa sprouts!) — The flavors, colors, and textures can be lively and incredibly appetizing to many palates. And, similar to non-vegetarian meals, vegetarian eats can be simple or complicated to prepare.

Numerous vegetarian websites, blogs, and cookbooks exist. Let's start wtih some favorite websites and blogs:

Cookbooks are also terrific resources of recipes for vegetarians, including:

  • "How to Cook Everything Vegetarian," by Mark Bittman will appeal to those who want simple vegetarian recipes.
  • "Veganomicon: The Ultimate Vegan Cookbook," by Terry Hope Romero is a classic. While all the recipes are vegan, you could easily adapt and add some non-vegan, but still vegetarian ingredients, such as milk or cheese.
  • "Moosewood Restaurant Cooks at Home: Fast & Easy Recipes for Everyday," by the Moosewood Collective. Actually, all of the Moosewood cookbooks are excellent!

These books, as well as other vegetarian cookbooks, are available at on- and off-line bookstores. For more information about vegetarianism, check out the Related Q&As. If you're a Columbia student, give Becoming a vegetarian — Columbia Health resources a quick read. Readers: We would love to hear your suggestions! Leave 'em in the comments!

Happy (vegetarian food) hunting,

Alice

Beta-carotene in produce

Dear Orange you curious too,

Beta-carotene is just one out of hundreds of a family of plant pigments termed carotenoids. You may have heard of some of the other plant chemicals (phytochemicals) — lycopene, lutein, alpha-carotene, and zeaxanthin, among others. In particular, beta-carotene is a provitamin A carotenoid: it can be made into vitamin A by the body. Some research has linked diets high in beta-carotene and vitamin A to lower rates of some kinds of cancer. (Similar studies on beta-carotene supplements haven't shown the same association.) Other carotenoids may have similar health-promoting effects. 

Carotenoids are found in fruits and vegetables that are red, orange, and deep yellow in color, and in some dark green leafy vegetables too. While there are no home tests, if you wish to compare different foods' beta-carotene content, check out the USDA National Nutrient Database for beta-carotene. Be advised that at the moment no DRIs (Dietary Reference Intakes) have been established for any of the carotenoids. However, there are recommended dietary allowances (RDAs) for vitamin A — 3000 IU (900 mcg) a day for men and 2310 IU (700 mcg) a day for women — and foods rich in beta-carotene can help you meet these levels.

It's always a good bet to eat lots of fruits and vegetables — especially ones of all different colors. Trying to include red, green, and orange vegetables or fruits every day can be attractive, tasty, healthy, and fun! For more information about beta-carotene, check out the related Q&As listed below.

Alice

Are yams an adequate alternative to hormone replacement therapy?

Dear Ana,

Wild yam (Dioscorea villosa) and Mexican yam have been marketed as alternatives to synthetic progesterone (not estrogen), which is a hormone taken by some women during menopause. These yams contain diosgenin, a plant substance that has a chemical structure similar to progesterone. In the laboratory, diosgenin can be converted to progesterone by using specific reagents and enzymes to carry out a series of chemical reactions. This transformation can only be performed in a lab — the same process does not occur in the human body. As a result, it's actually misleading for a manufacturer to term a wild yam supplement as "natural progesterone" because it is not progesterone, nor does it have any impact on a woman's hormone levels. Since diosgenin doesn't have hormonal activity itself, creams containing this substance are not effective.

In the United States, what is commonly referred to as a "yam" is actually a variety of sweet potato (ipomoea batatas). Yams are similar in shape to sweet potatoes, but are drier and starchier in taste, and are rougher and scalier in texture. Sweet potatoes are a good source of beta-carotene, vitamin C, folic acid, and some B vitamins. Predominantly grown in the Caribbean and Africa, yams are a good source of potassium, but contain no beta-carotene, and have lower levels of B vitamins, vitamin C, and folic acid than sweet potatoes. Eating sweet potatoes or yams will provide nutrients, but, as they contain neither progesterone nor estrogen, they won't affect a woman's hormonal balance.

Alice

Nuts about nuts: Are some better for health than others?

Dear Nuts for nuts,

What did one squirrel say to the other squirrel? "I'm nuts about you!" One variety of nut isn't necessarily healthier or better than another. All nuts are healthy, unless you have an allergy or sensitivity to one or more kinds. While individual types vary in nutrients, most nuts contain an array of vitamins and minerals, such as iron, magnesium, zinc, vitamin E, and small amounts of folate, copper, phosphorous, and calcium. Nuts may also contribute to one's daily protein and fiber needs.

The following chart provides nutritional information for some popular nuts. All numbers are for dry roasted, unsalted nuts. Some nuts are roasted in oil, which adds fat and calories without adding additional vitamins or minerals. In addition, some nuts are salted, which may greatly contribute to one's daily sodium intake. Based on that information alone, it seems that dry roasted, unsalted nuts are the way to get the best bang for your buck.

Nut type Calories(per oz.) Fat (g) Sat. Fat (g) Unsat. Fat (g) Protein (g) Fiber (g) Calcium
(% DRI)
Zinc (% DRI) Vit. E (% DRI) Magnesium (% DRI)
Peanuts 166 14 2 12 7 7 1.5 9 19 12
Walnuts 182 18 2 16 4 4 3 7 7 11
Pecans 189 19 2 17 2 2 1 15 8 9
Almonds 167 15 1 14 6 6 7 9 11 20
Cashews 163 13 3 10 4 4 7 15 1 18
Macadamia 200 21 3 18 2 2 2 4 1 7

Nuts are calorie dense foods, meaning they pack a lot of calories into a small amount of food. This can be helpful for people trying to gain weight, but also need not make them off limits to those watching their waistlines. For example, one ounce of most nuts equals about 18 to 24 nuts (a small handful for many, and a tiny handful for larger-handed folks), and contains between 165 and 200 calories. The majority of the calories in nuts is derived from their unsaturated fats — specifically, monounsaturated fat — which is more healthful than saturated fat.

Nuts offer so many valuable nutrients, and can be enjoyed in small servings as well. Why not try to:

  • Mix sliced nuts into plain rice, rice pilaf, or couscous.
  • Sprinkle slivered nuts onto vegetables or into salads.
  • Use slivered or chopped nuts as a yogurt topping.
  • Substitute diced nuts for croutons in salads.
  • Add chopped nuts to vegetable dips or soups.

In conclusion, it's great that you're nuts about nuts. No ifs, ands, or nuts about it!

Alice

Is margarine really better than butter?

Dear Baffled Over Butter,

You may be baffled over butter, but it sounds like you've got a good grip on chemistry! Some of the margarines sold in stores today are still made from oil that has been infused with hydrogen atoms, firming it up into a semi-hard or solid form at room temperature. This process is known as hydrogenation, and it allows the margarine to contain less saturated fat than butter. Unfortunately, hydrogenation also forms something known as trans fat, which actually does more damage to your body than saturated fat. (Both butter and margarine end up containing the same amount of total fat.)

Margarines made from hydrogenated oil usually appear in a solid stick form, similar to how butter is sold. Other kinds of margarines on the market today are made from non-hydrogenated oil, making them softer in texture and lower in calories, saturated fat, trans fat, and total fat. These soft margarines, which are commonly packaged in tubs and known as "soft-tub margarines," replace the hydrogenation process with small amounts of modified palm kernel and palm oil in order to make it softer and easier to spread.

Unlike margarine, butter isn't made from vegetable oil. Instead, butter is prepared from cream, contains saturated fat, and, because it's made from an animal source, also has cholesterol. Both saturated fat and cholesterol raise unhealthy cholesterol or LDL (low-density lipoprotein). Margarine is manufactured from vegetable oils, such as corn, soybean, or safflower oil, among others. Since margarine is based on plant sources, it doesn't contain cholesterol.

Because margarines don't contain cholesterol and are now made without trans fat, the American Heart Association recommends that soft margarine can be used instead of butter in recipes. Choose a margarine that contains less than two grams of saturated fat per tablespoon, no trans fat, and has liquid vegetable oil as the first ingredient.

If all this chat about fat has made you curious (or confused), check out Good vs. bad fats and "Good" and "bad" cholesterol in Alice!'s archives for more information.

Alice

Fiber supplements — Safe to use every day?

Dear Regular,

Some of the fiber supplements (available in powder and pill forms) you are referring to are designed to help alleviate constipation, and are to be used for a limited time only. That's because if a person has chronic constipation, the cause needs to be determined. Other products can be used as supplements, as long as there are no underlying medical issues, such as chronic constipation. Two steps to determine how you use supplements are 1) read the labels carefully to find a fiber product that can be used daily, and 2) speak with your health care provider to determine if you should be taking a daily supplement.

For people who experience constipation or other irregularity with their bowel movements, some causes may be: 

  • Inadequate fiber consumption
  • Lack of exercise
  • Insufficient fluid intake
  • Change in one's daily routine
  • Ignoring the urge to move one's bowels
  • Certain diseases
  • Some medications

Luckily for you and anyone who needs more fiber, fruits and vegetables aren't the only good sources for getting more fiber into your diet. Here are some fiber boosting tips:

  • Have a higher fiber cereal for breakfast — try to select one that contains at least 5 grams per serving.
  • Add beans to salad, or dine on a cup of chili for lunch. Each ½ cup of beans contains 3 to 4 grams of fiber.
  • Choose whole wheat bread, which has 2 grams of fiber per slice.
  • Munch on berries (one serving = ½ cup), pears (1 medium with skin), and oranges (1 medium). If you eat just two servings of these a day, you'll add 7 to 8 grams of fiber.
  • Snack on popcorn (go for air-popped). You get 1 gram of fiber per cup (equal to about 2 to 3 handfuls).
  • Have a baked potato, which has almost 4 grams of fiber.
  • Chomp on a medium carrot, which can add 2 grams of fiber.

Part of the benefit of getting fiber through food is that you will also take in the abundant vitamins, minerals, and plant chemicals (phytochemicals) that are present — you'll get lots of important nutrients, such as vitamin A, thiamin, riboflavin, niacin, folate, vitamin C, vitamin E, chromium, copper, iron, magnesium, potassium, and zinc; also in these foods are disease fighting plant chemicals, such as anthocyanins, alpha and beta-carotene, isoflavonoids, and phytosterols, among others.

If you do take a fiber supplement, you'll want to be careful because too much fiber can bind important minerals, such as calcium, iron, and magnesium, decreasing their absorption by the body. If you have more questions about your use of supplements, it would be a great idea to ask your health care provider, who knows your medical history and can recommend the best source of fiber for you. If you're a Columbia student, you can make an appointment with Medical Services (Morningside) or the Student Health Service (CUMC).

Wishing you continued regularity,

Alice

What's that growing in the refrigerator?!? A guide for storing and eating leftovers

Dear Leftover lover,

Enjoying holiday leftovers is a favorite tradition. However, food-borne illness resulting from eating leftovers long past their prime can dampen holiday cheer. Typical symptoms of food-borne illness, caused by bacteria, include abdominal pain, diarrhea, and vomiting.

Two different families of bacteria are found in food: pathogenic bacteria and spoilage bacteria.

Pathogenic bacteria cause food-borne illness. Leaving food out at room temperature (about 72° F or 22° C) for extended periods of time encourages growth of these types of pathogens. These bacteria grow rapidly when in the "danger zone," which is between 40° to 140° F (4 to 60° C). They are difficult to detect, because they don't affect the taste, smell, or appearance of food. Safe food handling and proper food storage are the best defenses against pathogenic bacteria. For detailed instructions on how to keep food safe for consumption, check out the Partnership for Food Safety Education web site.

Spoilage bacteria can grow at lower temperatures, such as ones found in refrigerators. These bacteria cause food to taste, look, and/or smell badly. Most of the time, spoilage bacteria won't cause illness, but they do make food much less appealing to eat.

Leftovers need to be kept in airtight containers recommended for reuse and food storage in the refrigerator and/or freezer. Leftovers can also be wrapped in two layers of plastic wrap and/or foil or in a plastic storage bag (with the food inside wrapped in a layer of plastic wrap or foil) to maintain moisture and prevent absorption of odors from other foods. When freezing leftovers, adding freezer tape also helps keep air and moisture out, and protects from freezer burn. Here are some safe time limits for keeping some common meat and poultry leftovers:

Food Item

Refrigerator Storage Temp.
(40° F / 4° C)

Freezer Storage Temp.
(0° F / -18° C)

Cooked turkey or chicken, plain

3 to 4 days

4 months

Cooked turkey or chicken dishes

3 to 4 days

4 to 6 months

Turkey or meat broth, gravy

1 to 2 days

2 to 3 months

Lunch meat

Unopened, 2 weeks
After opened, 3 to 5 days

1 to 2 months

Cooked fried chicken

3 to 4 days

4 months

Cooked chicken nuggets or patties

1 to 2 days

1 to 3 months

Cooked meat and meat casseroles

3 to 4 days

2 to 3 months

For more information on the safe keeping of most foods, visit the U.S. Department of Agriculture (USDA) Food Safety and Inspection Service web site. Enjoy your holiday meal today, tomorrow, and the next day,

Alice

A sweetener called stevia

Dear Skeptical,

Your skepticism is warranted, considering the label "all natural" does not have one, standard definition or imply “risk-free.” In order to be approved by the Food and Drug Administration (FDA), sweeteners marketed as “Stevia” may contain only one highly refined component of the stevia rebaudiana plant, called Rebaudioside A. Due to potential health risks, no other components of the stevia plant have been approved by the FDA as food additives or sugar substitutes. Non-food products (often labeled as dietary supplements) containing less refined stevia ingredients are available, and some are even deemed “safe for consumption.” However, the FDA recommends waiting for more conclusive research before consuming large quantities of supplements containing stevia-derived ingredients other than Rebaudioside A.

In addition to Rebaudioside A, most FDA-approved stevia sweetener products also contain fructooligosaccharide, a sugar extracted from non-stevia fruit sources. Some studies show that fructooligosaccharide may actually promote the growth of healthy bacteria, relieve constipation, regulate lipid metabolism, and promote immune system health. Additionally, these sugars may be less detrimental to oral health than table sugar, and may help to treat glucose intolerance. Rebaudioside A and fructooligosaccharide are both approved by the FDA as food additives.

Although some empirical studies show no negative side effects of consuming unrefined stevia plant products and deem them “relatively safe” and “nontoxic,” the FDA has expressed safety concerns related to these products. Such concerns include negative effects on the reproductive, cardiovascular, and renal systems as well as blood sugar regulation issues. Other concerns include the stevia plant’s potential ability to damage genetic material, but independent scientific studies have determined that this type of gene damage is only possible in a laboratory environment, not in the human body. Stevia proponents also cite the plant’s inability to be digested (hence, the reason why it is calorie-free) as evidence that it simply passes through the body without causing any damage.

When it comes to sweeteners and food additives, Rebaudioside A is the only FDA-approved component of the stevia plant. Considering the inconclusiveness of existing research, unrefined stevia supplements and other non-food products should be consumed cautiously. Good work keeping yourself informed before you ingest!

Alice

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