You are here: Home / HPRC Blog
RSS Feed for Nutrition


Welcome to the HPRC Blog. We've got lots of information here, from quick tips to in-depth posts about detailed human performance optimization topics.

HPRC Fitness Arena: Nutrition

Spice up your diet!

HPRC Fitness Arena: Nutrition, Total Force Fitness
Learn how adding a little spice to your diet can enhance performance and improve health.

Spices add flavor and color to many foods. But did you know they also might improve your performance while offering you protection from many diseases, including heart disease and cancer?

Your body’s cells continuously produce large quantities of what scientists call “free radicals”—highly reactive molecules that can damage cells. Ordinarily, your cells also produce antioxidants to neutralize these free radicals. But exercise, stress, and environmental pollutants can cause an imbalance between your body’s antioxidants and its free radicals. That’s where spices can come into play.

Not only do spices such as cinnamon, allspice, oregano, and turmeric (and others) demonstrate high antioxidant activity, scientists think they might actually help your body produce its own antioxidants. Some research suggests that eating spices as part of a diet rich in whole grains, fruits, and vegetables can prevent inflammation (a key player in the development of many diseases) and protect your body’s cells from damage caused by free radicals.

Get creative! Sprinkle a little cinnamon over your morning oatmeal, add a bit of allspice to a post-workout recovery shake, or stir some oregano or turmeric into your vegetable soup. A little bit goes a long way. Not only will you get a boost of flavor, you just might take a step toward better health and performance.

Focus on food, not supplements

When it comes to nutritional value, dietary supplements just don’t measure up. Choose whole foods such as fruits and vegetables instead to fuel your performance.

Food and health are hot topics these days. Just turn on the TV, pick up a magazine, or glance at the margins of your social networking site and you’ll hear and read about the supposed health benefits of dietary supplements containing this or that food component and the promises that they will “burn belly fat” or some similar claim.

Many of these promising food components belong to a group of compounds referred to as phytochemicals—chemicals produced by plants as a means of protecting the plants from various diseases.

Interestingly, when you eat plants (such as fruits and vegetables), the phytochemicals they contain might protect you from disease too. Researchers have found that people who eat a lot of fruits and vegetables have lower rates of heart disease, cancer, diabetes, and many other diseases. Scientists haven’t discovered exactly how these compounds work to protect us, but they have discovered that they seem to have a synergistic effect. That is, the compounds seem to work better in combination, especially when they are supplied in their natural form—whole foods. Consuming isolated single compounds, as in dietary supplements, rarely has the same beneficial effect as eating the whole food. See these resources about fruits and vegetables and how they may impact your overall health.

Focusing on single nutrients (in pill form) is not only expensive, it just doesn’t offer the promise that a balanced, varied diet can. Focus on food, instead. For more information about the benefits of food versus dietary supplements, check out this OPSS brochure, “Nutrition: Fueled for Fitness.”

Alphabet soup for nutrition

HPRC Fitness Arena: Nutrition, Total Force Fitness
Filed under: Diet, Nutrition
Sometimes it seems that nutritionists have nearly as many acronyms as the military! Here’s a sampling of the “alphabet soup” of some nutrition-related terms and their meanings.

Nutrition experts at the Institute of Medicine—or IOM—of the National Academies of Sciences gather extensive information to make nutrition recommendations for the American public. One major result is known as the Dietary Reference Intakes, or (acronym number one) DRI. You might come across some of the DRI’s acronyms when reading how to fuel your body or considering a dietary supplement, so it’s helpful to know what they mean and where they came from.

The Estimated Average Requirements (acronym number two: EAR) are the average amount of nutrients that half of all healthy people need each day. EARs differ depending on life stage and gender. Remember, though, they’re simply an average. Scientists use statistics based on this average to calculate the Recommended Dietary Allowances (acronym number three: RDA).

The RDAs are the daily nutrient goals for essentially all healthy people, again based on life stage and gender. For example, the RDAs of some nutrients (such as vitamin C) for a 13-year-old boy are very different from those for a 25-year-old pregnant woman.

The Adequate Intakes (acronym number four: AI) are the—you guessed it—adequate daily amounts of nutrients that healthy people of a particular life stage or gender need. AIs are given when there isn’t enough scientific evidence for a stronger recommendation, that is, an RDA. For example, the IOM suggests an AI for one type of omega-3 fatty acids—alpha linoleic acid—of 1.6 grams per day for men and 1.1 grams per day for women because scientists just aren’t sure yet how much is optimal.

Tolerable Upper Intake Levels (fifth and final acronym, for now: UL) are the highest daily amounts of nutrients that you can consume without risk of toxicity. Many vitamins and minerals—even essential ones—can be toxic when consumed in excess. For example, because too much vitamin A can cause liver damage, a UL has been established for this essential nutrient.

So, if you remember nothing else, remember to get your RDAs and AIs every day, but don’t exceed the ULs!

The USDA Food and Nutrition Information Center provides links to the DRI Tables, but generally speaking you can meet all your daily nutrient intake goals (the RDAs and AIs) by following a healthy diet that includes lean proteins, whole grains, fruits, vegetables, and low-fat dairy products. And be aware that recommendations do change. IOM reviews the most current nutrition science and updates the tables when necessary to keep up with the latest knowledge, which means better health for Warfighters and their families.

Get to know HPRC better

Learn about all the areas HPRC covers and what “human performance optimization” is.

The Human Performance Resource Center is here to serve Warfighters and their families, commanders, and healthcare providers. If you’ve visited before, you probably know that we focus on “total force fitness.” But do you really know what that means—or how HPRC got started? If you’re curious, check out this PDF that describes HPRC, what we do, and the vast amount of information we cover. In addition, you may have noticed that we use the term “human performance optimization” throughout our site; this article also explains what that means.

DoD’s DMAA report

The DoD Safety Review Panel has completed its review of DMAA, and the report is now available on HPRC’s website. The result is that DMAA-containing products will no longer be sold on military installations.

The Department of Defense (DoD) Safety Review Panel published their findings on DMAA in a recent report now available through HPRC. The Assistant Secretary of Defense for Health Affairs asked the Safety Review Panel to evaluate the safety of DMAA-containing dietary supplement products. The Panel has recommended that the sale of DMAA-containing products be prohibited in all military exchanges.

HPRC maintains a list of dietary supplement products containing DMAA and periodically updates this list. The most recent version can be found on HPRC’s website. Note that, as of the FDA announcement in April 2013, DMAA is illegal in the U.S. as an ingredient in dietary supplements. For more information, visit the OPSS FAQ about DMAA. Operation Supplement Safety (OPSS) can provide service members and their families with information to make informed decisions about dietary supplement use. For the full DoD Safety Review Panel report, see the link on HPRC's Dietary Supplements web page.

Grapefruit and Drugs: A sour combination?

HPRC Fitness Arena: Nutrition, Total Force Fitness
Grapefruit and grapefruit-containing products can interfere with how your body breaks down some drugs.

Grapefruit is a tropical fruit known for its lip-puckering flavor. It contains vitamin C and many other nutrients and is a regular feature at the breakfast table. Grapefruit and its extracts also show up as flavoring agents in beverages and are sometimes added to dietary supplements.

Despite its many health benefits, grapefruit can pose a risk for people taking certain drugs. That’s because grapefruit can affect the way drugs are broken down or transported in the body—potentially increasing or decreasing the drugs’ effectiveness.

If you enjoy eating grapefruit or grapefruit-containing products, be aware of potential interactions when taking medication. If you take prescription or over-the-counter drugs, ask your doctor or pharmacist if you should avoid grapefruit. This consumer update from the Food and Drug Administration has more information.

Don’t pass the salt!

HPRC Fitness Arena: Nutrition, Total Force Fitness
Filed under: Diet, Nutrition, Sodium
Researchers agree that most people need to reduce their sodium intake, but a recent Institute of Medicine study also suggests some individuals should be careful not to cut back too far.

Sodium—a component of table salt—is an essential element. It helps your muscles and nerves function correctly and maintains the proper balance of your body’s fluids. However, too much sodium in your diet may increase your risk of high blood pressure, heart attack, stroke, and certain types of cancer.

The average American consumes about 3,400 milligrams (mg) of sodium every day, mostly in the form of salt. But the current Dietary Guidelines for Americans recommends that adults limit their sodium intake to just 2,300 milligrams per day—roughly the amount in one teaspoon of table salt.

The guidelines also recommend that certain “at-risk” groups limit their sodium intake to about 1,500 mg per day: adults over the age of 51, African Americans, and people who have high blood pressure, diabetes, or kidney disease.

Recently, the Institute of Medicine (IOM) looked at the evidence supporting the current recommendations regarding sodium intake. IOM concluded:

  • Research supports current recommendations to reduce sodium intake to about 2,300 mg daily.
  • More research is needed to support the recommendation that those “at risk” should cut back to 1,500 mg or less a day.

Bottom line? If you’re in an at-risk group, speak to your doctor or registered dietitian about whether you should reduce your salt intake. For just about everyone else: Cut back on the salt.

How? Most of the sodium Americans consume comes from processed foods—tomato sauce, soups, canned foods, bread, and prepared mixes—but it can also come from foods naturally high in sodium—cheese and some types of seafood. Also, many restaurant foods are high in sodium, but sometimes you can request low sodium items. The best way to ensure a low sodium diet is to eat whole foods such as fresh or frozen fruits and vegetables; lean, unprocessed poultry and fish; unsalted nuts; whole grains; and low-fat dairy products such as skim milk or yogurt.  For more information, check out this CDC web page.

For additional information and other conclusions from the study, see the news release (which includes a link to the full study) from the National Academies.

What are hidden sources of sugar?

HPRC Fitness Arena: Nutrition, Total Force Fitness
 Here are some “sweet spots” you can watch out for on the ingredient labels of foods, drinks, and dietary supplements if you are watching your sugar intake.

Sugar can be present in foods even when we don’t know it. Some hidden sources of sugar on listed food labels are high-fructose corn syrup, brown rice syrup, brown sugar, honey, maple syrup, glucose, (or dextrose), lactose, sucrose, and the sugar alcohols sorbitol, zylitol, mannitol, and maltitol. Those people watching their sugar intake should read labels carefully to spot hidden sources.

What is Tribulus terrestris?

What is Tribulus terrestris and why is it used in some dietary supplement products?

Tribulus terrestris is used as an ingredient in some dietary supplement products marketed as testosterone “boosters” and/or to enhance muscle strength. What is it and does it work? Read this OPSS FAQ about Tribulus terrestris to find out. Also, be sure to check the OPSS section often, as we add answers to other questions about ingredients in performance-enhancing and bodybuilding supplements. OPSS can help you learn how to choose supplements safely.

If you have a question about a particular dietary supplement ingredient or product, and you can’t find the answer on our website, please use our “Ask the Expert” button located on the OPSS home page.

Pass the gum please!

HPRC Fitness Arena: Nutrition, Total Force Fitness
If you’ve ever seen xylitol listed as an ingredient on your favorite gum label, it may not be what you think it is. Read about its potential benefits.

Do you know that many kinds of chewing gum—including the gum in MREs—contains a sugar sweetener called “xylitol”? This natural sweetener can be good for your teeth and gums! Xylitol has been found to offer preventive dental benefits, including reduced bacteria and acids that cause cavities and significant decreases in plaque. Most studies have shown that the use of chewing gum or mints with xylitol three to five times a day, especially after eating, result in the greatest benefits. Other sugar-free sweeteners used in gum and mints offer some oral health benefits, but for maximal benefits use products with xylitol. For more information, read this health fact sheet xylitol and how it can protect your teeth. Although chewing gum or mints with xylitol helps reduce cavities, they do not replace the benefits of regular brushing and flossing.

RSS Feed for Nutrition