March/April 2004 Volume 8, Issue 1
Current research surrounds us with evidence of the increasing need for weight reduction by many adult Americans, and no other angle is getting as much attention today as low carbohydrate diets. Although there are a number of variations, the Atkins' diet is probably the most talked-about. While the different low carbohydrate diets vary in what they allow, they do have a few traits in common -- if carbohydrate is restricted, the diet is centered around foods high in protein and often fat.
This issue of The Spotlight focuses on facts about fat and the particulars of protein in our diets. We take a look at the nutritional composition of red meat, as well as what plant-based protein foods have to offer. You'll find an update on omega-3 fats, and the latest info on fish in our diets. Throughout the articles, we have included the latest recommendations, or Dietary Reference Intakes (DRIs), for the nutrients discussed.
All this low-carb talk leaving you hungry for something? We know what you're looking for -- our upcoming issue will feature the many faces and facts of carbohydrates. There is something for every body in The Spotlight!
Low carb diets may be more effective in short term weight loss than are conventional weight loss diets. Followers of low carb diets also tend to generally eat fewer calories than they need for weight maintenance, which accounts for some of the weight loss.
Fluid intake should be increased by those following high protein diets such as Atkins', South Beach and the Zone. These diets provide 30% — and sometimes much more — of calories from protein, compared to the typical American diet that provides 20% or less of calories from protein. This increase in dietary protein requires more work by the kidneys, which have to metabolize the increased amounts of nitrogen in protein. Severe carbohydrate restriction also causes fatigue, which makes it harder to do physical activity, and ketosis, which causes a health crisis in some people and bad breath in most people.
Long-term studies have yet to be completed that examine the safety and effectiveness of low carb diets. For example, risk factors for chronic health problems such as hypertension and various cancers during long-term use of a diet that restricts most fruits and whole grains need to be investigated. The National Institutes of Health is currently sponsoring a multi-centered clinical trial on the Atkins' diet to help clarify health effects associated with its use.
Most Americans would benefit from eating fewer refined carbohydrates, such as sugars and white flour, and increasing their consumption of whole grain foods, fruits, vegetables and legumes. Additionally, keeping intake of saturated fats to no more than 7 to 10% of calories is beneficial for heart health. (MH)
What food provides protein, iron, fat, vitamins, and minerals to your diet? The answer is meat. While a wide variety of foods are often included in this group, for this discussion we will focus on red meats such as beef, veal, buffalo, lamb, and, pork. All are great sources of essential nutrients.
One of the most important nutrients meat provides is protein. Protein assists the body in growth and tissue repair as well as the generation of infection-fighting antibodies. Protein is comprised of compounds called amino acids. The body generates some amino acids while others, the essential amino acids, must be gained from the diet. Since meat contains all of these essential amino acids, it is considered a source of "high quality complete" protein. Plant-based protein products, although a great option, lack at least one of these essential amino acids. While the body is able to pair up amino acids from the variety of foods eaten through the day to build complete protein, meat is a one-stop protein source, and a small amount goes a long way. For example, a 3-ounce portion of lean beef, lamb, or pork can provide up to half of the daily dietary requirement for protein. Proportionally speaking, the leaner the cut of meat, the higher the protein content, so consumption of lean meats over their "fattier" counterparts is recommended.
Another essential nutrient (mineral) which meat, especially red meat, provides is iron. The type of iron present in meat is primarily heme iron, the type most easily utilized by the body. Plant products contain the less utilized non-heme iron, but when eaten with meat, its level of absorption increases. Protein and iron work hand-in-hand to create hemoglobin, which carries oxygen and carbon dioxide throughout the body. Hemoglobin also assists in the growth of body tissue and combats anemia. This is why adequate iron intake is so important for growing children and pregnant or menstruating women -- two groups that are often iron deficient. A 3 oz portion of lean beef provides approximately 2.5 to 3.0 mg of iron while the same amount of pork provides 1.2 mg of iron. The recommended RDA for women is 8 to 18 mg of iron. Eating the suggested amounts of meat daily along with plant products high in iron will ensure that the RDAs of this important mineral are met. Pregnant and lactating women need a whopping 27 mg per day, and typically require a supplement to meet this need.
Additional minerals found in meat include phosphorus, magnesium, sodium and zinc. One of meat's greatest attributes is that it is a wonderful source of zinc. Zinc is necessary for growth and development, immune stability, healing and assists in taste enhancement and appetite control. Beef is the number one source of zinc in the American diet with a 3 oz portion providing 6 mg of the RDA of 8 to 13 mg (dependent upon age and gender). The same 3 oz portion of lamb will provide 4.5 mg of zinc.
Meat is a well know contributor of fat in the diet. Some shy away from its consumption, but fat is an essential nutrient that assists in the uptake of vitamins A, D, E, and K. The fat found in meat is not just saturated, but also "heart healthy" monounsaturated and polyunsaturated. Choosing lean cuts of meat, cooking with low fat methods, and limiting consumption to recommended portions can help control overall fat intake while reaping the benefits of meat.
Last but not least, meats are wonderful sources of the B vitamins responsible for the growth, repair, and maintenance of the body. Red meats provide about 50% of vitamin B12 found in food, 27% of the niacin, and 25% of vitamin B6.
Incorporating a variety of meat into the diet while being mindful of cut, cooking method and portion size can be the first step in reaping the nutrient benefits of this important food group. Meat — a multi-nutrient food vital for bodily growth, repair, and rejuvenation.
(Recommended Dietary Allowance for Protein)
| Male | Female | ||
| 0-6mo | 9.1g/day | 0-6 mo | 9.1g/day |
| 6mo-1 yr | 13.5g/day | 6mo-1yr | 13.5g/day |
| 1-3 yr | 13 g/day | 1-3 yr | 13g/day |
| 4-8 yr | 19 g/day | 4-8 yr | 19g/day |
| 9-13 yr | 34 g/day | 9-13 yr | 34g/day |
| 14-18 yr | 52 g/day | >14 yr | 46g/day |
| >19 | 56 g/day | Pregnant/nursing | +25g/day |
Source: Modified from Food and Nutrition Board, Institute of Medicine: Dietary reference intake for energy, carbohydrate, fiber, fatty acids, cholesterol, protein and amino acids. Washington, DC .2002. National Academy Press. (KH)
It's not been too long ago that nuts were considered simply as tiny, high-calorie packages of fat, and we tried to stay away from such temptation, if we knew what was good for us. Well, as it turns out, we didn't know just how good nuts are for us! Research continues to show that people who regularly eat nuts appear to have lower cholesterol levels, and may have a lower risk of heart disease. The Food and Drug Administration (FDA) has allowed manufacturers of certain types of nuts to claim the moderate evidence of the health benefits nuts provide. Nuts have transformed from a "no-no" to a "now!" food, and the turnaround has been rapid.
Nuts' rise from the nutritional basement to bright star is part of the dramatic rethinking of the role of fat in the diet, experts believe. Recent studies reaffirm growing understanding that the type of fat matters in the diet, and that some fat is good. Nuts are naturally high in unsaturated fat _ the type found in olive and canola oils as well _ and offer many other valuable nutrients as well. They are excellent sources of fiber, vitamin E and magnesium. As a protein source, nuts are excellent contributors. A 1/4 cup serving of peanuts yields 9 grams of protein - about the same as an ounce of roast beef or tuna. Some nuts -- walnuts, for example -- are excellent sources of omega-3 fats. And there's more! Nuts also contain resveratrol, a phytonutrient scientists are studying for its protective effects in the body. Just recently the FDA announced that whole and chopped walnuts can display a qualified health claim on their label regarding the reduced risk of coronary heart disease. FDA's review concluded that supportive research shows that eating 1.5 ounce of walnuts per day may reduce the risk of coronary heart disease when consumed as part of a low saturated fat and low cholesterol diet and not resulting in increased caloric intake.
Nuts are nutritious, no doubt about it. But aren't they high in calories? While an ounce of nuts contains about 160 to 200 calories, they certainly aren't empty calories. Portion control is the key with nuts, as it is with most foods. Instead of opening a can or jar of nuts and downing the contents, consider ways to include a few nuts strategically throughout the day. For starters, many breakfast cereals contain nuts -- there are lots to choose from. Add a few nuts to a carton of yogurt, a bowl of oatmeal, or sprinkle some over the pancakes as they are cooking. Pack a few in your backpack, pocket or purse for a mid-morning snack -- and don't forget peanut butter! At lunch, add a tablespoon of nuts to a salad or select a sandwich bread with nuts baked in. For dinner, add peanuts, walnuts or cashews to the stir fry, or try slivered almonds to top the vegetable.
No matter how nuts are included throughout the day, they don't necessarily cause weight gain. Separate studies at Purdue, Harvard and Loma Linda universities researched the effect of nut consumption on weight control, and none found adding nuts to the diet caused weight gain. (SP)
2) Food models. National Dairy Council, 1998.
3) U.S. Food and Drug Administration. FDA Moves forward on qualified health claims. Accessed at http://www.fda.gov/bbs/topics/news/2004/NEW01044.html on 4/05/04
According to a 2001 report by the Economic Research Service of the United States Department of Agriculture, Americans are choosing a wider variety of protein foods than in the past. Less red meat and more chicken and fish are being consumed. In addition, we are consuming more plant-based forms of protein with soy being the primary source.
Soy comes from soybeans, a member of the legume family. Legumes (dried peas and beans) are technically classified as vegetables, but unlike most vegetables, they provide a significant amount of protein. For example, a half a cup of cooked dried beans provides 7-9 grams of protein, roughly equivalent to an ounce of meat. Soy protein is nutritionally equivalent to protein found in eggs, milk and meat. It offers a "complete" protein profile including all essential amino acids (those not made by the body). Other legumes are also very good sources, but are not complete protein, having two limiting amino acids (cysteine and methionine). This is not a problem as long as they are eaten as part of a varied diet that includes cereals or grains. A favorite combination in many cultures is beans and rice or lentils and pasta. Legumes provide other valuable nutrients other than protein: fiber, thiamin, folate, calcium, phosphorus, potassium, iron, zinc, and phytochemicals. In addition, they contain oligosaccarides (raffinose and stachyose) that promote a healthy bacterial balance in the gastrointestinal tract.
In comparison to animal protein, soy protein has the advantage of less saturated fat and no cholesterol. In 1999 the Food and Drug Administration approved a health claim that food companies may put on their food labels stating that a daily diet containing 25 grams of soy protein may reduce the risk of heart disease. In order to display the claim, the food must have at least 6.25g of soy protein/serving, be low in fat (less than 3g), saturated fat (less than 1 g), cholesterol (less than 20 mg) and low in sodium (less than 480 mg if in an individual food). The cholesterol-lowering effect of soy protein is greatest in people who have high blood levels of cholesterol. Soy protein seems to improve arterial elasticity and protect LDL cholesterol from oxidation (Potter, 1998).
Soy is a versatile food that can take on many different flavors and textures. It can be made into products that imitate meat (meat analogs such as soy burgers or sausage). Tofu, as an example, is a popular form of pureed soybean that can be used as meat substitute in casseroles or even custard-like desserts.
Examples of soy products and their corresponding protein content are:
Product Amount Grams of Protein
Because of the high quality of soy protein, the FDA has approved the use of soy-based infant formula for full-term infants when milk-based formula is not well tolerated (as in the case of lactose intolerance or milk allergy).
As additional health benefits of soy related to chronic diseases (cancer, osteoporosis and diabetes) are being studied, consumer trends show an increase in consumption of plant-based protein foods that can be healthy, and often inexpensive, alternatives to animal protein.
Sources: Krause's Food, Nutrition, & Diet Therapy 11th ed. Mahan, L. Kathleen. Escott-Stump,Sylvia. Saunders Publishing. 2004. Soy: Health Claims for Soy Protein. Henkel, John. FDA Consumer. May-June 2000. Vegetarian Nutrition. Sabate, Joan. CRC Press. 2001. pg 428-429. University of California at Berkeley: The Wellness Encyclopedia and Food and Nutrition. Random House. 1992. (KH)
The July/August 2001 issue of The Spotlight highlighted benefits of foods high in omega-3 fats, listed good dietary sources, and included special tips for buying and storing these foods. However, an important piece of information was missing: the amount of omega-3 fat we need. This information was absent in 2001 because the amount was not known. In 2002, the Food and Nutrition Board of the National Academy of Science issued recommendations for dietary intakes of omega-3 fat. In addition to these recommended intakes, the Food and Drug Administration approved a health claim about omega-3 fat in July 2003 that specifically cites walnuts, a source of omega-3 fat.
As described in the lesson, Omega-3s: Fats You Should and Can Eat, three molecules are denoted as omega-3 fats: alpha linolenic acid (ALA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA). EPA and DHA are found in animal foods, whereas ALA is only available from plants. All three molecules have the same bonding arrangement denoting them as an omega-3 fat, but they are not equal. ALA is essential in our diet. Humans cannot make ALA, but are able to make EPA and DHA from ALA. As a result, the dietary recommendations of omega-3 fat intake are based on our needs for ALA and factors that influence our ability to convert ALA to EPA and DHA. In our bodies, the forms of omega-3 fat that are most functional however, are EPA and DHA. Given this fact, the complexity of ALA conversion, and the listing of EPA and DHA content in food composition tables, some researchers have questioned the logic of stating these recommendations only in terms of ALA intake.
For now, infant recommendations, based on breast milk content, are for all omega-3 fats; for all other age groups recommendations are only in terms of ALA. EPA and DHA intake is encouraged because of their protective effect against heart disease, but because they are more potent than ALA, it is impossible to issue a blanket omega-3 fat recommendation. Based on available evidence, the only Acceptable Macronutrient Distribution Range (AMDR) set is for ALA: 0.6 to 1.2 percent of energy intake. Up to ten percent of the AMDR can be EPA and/or DHA.
Walnuts, one of the highest sources of ALA, may be labeled with the following health claim: "Supportive, but not conclusive research shows that eating 1.5 ounces per day of walnuts as part of a diet low in saturated fat and cholesterol may reduce the risk of heart disease. See nutrition information for fat content." 1.5 ounces is about a handful of walnuts. This amount of ALA is equal to that found in a tablespoon of flaxseed, 2 ½ cups of soybeans or 25 cups of leeks.
New numbers are nice, but don't necessarily simplify the issue of knowing how much omega-3 fat to eat.
An interview with Dr. Delores Chambers, Assistant Professor
The corridors of Justin Hall are often filled with tantalizing aromas coming from the Science of Foods labs taught by Assistant Professor Delores Chambers. HN 413, a four-credit course that includes three lectures and three sections of a four-hour lab each week, attracts about 60 students each semester. Dr. Chambers also teaches a distance version of this course, where students complete the lab work at home and send her pictures to document their work as it progresses, in addition to answering unit questions.
Chambers, who also co-directs the Sensory Analysis Center, is active in a variety of funded projects. "I love the many aspects," Chambers says of her work. Her research focuses on product attributes and evaluation of sensory panel performance, measurement of consumer perceptions of products, nutrition and health information, and the influence of health and price on consumer acceptance of products.
For one project, Chambers is developing videos in collaboration with the Kansas Family Nutrition Program to teach viewers how to best cook different kinds of meats. She also is collaborating on a project with Dr. Karen Schmidt in the department of Dairy Science to study the aftertaste of milk and teens' consumption of dairy products.
Chambers and a staff of three full-time professionals and 15 trained sensory panelists, along with 13 undergraduate and graduate students, complete about 60 sensory research projects each year, most of which are industry-sponsored. The Center also hires approximately 300 consumers from the general public each month to complete sensory tests on a wide variety of products, both food and non-food.
Chambers is one of only five U.S. representatives to the
Sensory and Marketing division of the International Organization
for Standardization, and she chairs the U.S. Technical committee.
She recently led their workshop for U.S. students graduating in this field
of study. She also directed a workshop using sensory analysis methods
for business professionals last fall in Thailand, and she will head
the delegation for setting sensory standards for international trade
this
spring in Hungary. In addition, Chambers serves on the
sensory division long-range planning committee for the Institute of
Food Technologists. She is the author of more than a dozen
scientific publications.
Chambers currently supervises five M.S. students, who hail from California to Peru to the Far East. She herself is a product of K-State's graduate program, earning a Ph.D. in Sensory Analysis in 1994 when she was known by her maiden name, Delores Heisserer. She returned to K-State's department of Human Nutrition eight years ago after working at the Kellogg Company managing sensory evaluation programs worldwide, at a marketing research company in New York, and as an intern at Coors Brewing Company in Colorado. Chambers received a B.S. in computer science and marketing management from Southeast Missouri State University.
Chambers, who was a middle child among seven siblings, has
an eight year old son. She is married to Dr. Edgar Chambers IV
(another HN faculty member, featured in the Sep/Oct 2001
Spotlight.) A culinary herb gardener, she also
enjoys travel, reading and doing needlework, genealogy
and scrapbooks. (MH)
Here's a recipe that has excellent nutrition and delicious flavor to offer. It's satisfying and inexpensive to prepare!
The U.S. Food and Drug Administration (FDA) advises that pregnant women, women who may become pregnant, nursing mothers and young children NOT eat any shark, swordfish, king mackerel or tilefish, since these fish species contain harmful levels of methyl mercury. Individuals in this group should eat no more than 12 ounces per week of all other types of cooked fish and no more than 6 ounces of albacore tuna. They should choose a variety of different species, such as shellfish, canned fish, smaller ocean fish or farm-raised fish.
State and local health departments can be contacted for specific recommendations about eating fish caught
or sold in your area. For example, freshwater fish caught in Kansas rivers and lakes currently do not have
advisories for mercury, but may have advisories about other pollutants, such as the insecticide chlordane. For
complete information, see Nutrition in the News at
http://www.oznet.ksu.edu/humannutrition/newnews.htm (MH)