Nutrition: wading through current controversies and confusion

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Nutrition wading through current controversies
and confusion
Heidi Wengreen, R.D., Ph.D., Assistant Professor
of Nutrition, Utah State University Heidi.Wengreen
_at_usu.edu
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Objectives

• Part I Guidelines and tools for the critical
  interpretation of nutrition news
• Part II Current topics of controversy/confusion
• Part III Probiotics ? self discovery

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Top 3 sources of consumer information
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Common forms of inaccuracy in Media reports on
nutrition information

• Reporting a correlation as a causation.
• Generalizing a studys results to a broader
  population, not represented by the study.
• Exaggerating the size of an effect.
• Using a single link in a chain of events to make
  predictions and events in the future.

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Terminology

• Meta-analysis
• Randomized, controlled, double-blind study
  gold-standard
• Prospective cohort study
• Case-control study
• Cross-sectional study
• Case-study
• Phase1 study

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Questions to ask about a research report
(American Dietetic Association position paper)
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Things to remember

• The latest study isnt the greatest study
• Dont just look at the bricks, look at the
  whole house

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Cant see the forest for the trees

• Fruit Juice Consumption Not Related To Overweight
  In Children, Study Suggests (May 23, 2008)
  Despite studies that assert otherwise, 100 fruit
  juice consumption is not related to overweight in
  children, according to a new ..
• Study Shows Fruit Juice/Drink Link To Children's
  Weight Gain (Mar. 29, 2007) Australian
  schoolchildren who drink fruit juices and fruit
  drinks are more likely to be overweight or obese
  than those who don't, Deakin researchers have ..

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• Read the following news story with a critical
  eye.
• Good news for the summer
• Beta-carotene helps to protect
• against sunburn (June 3, 2008,
• PRNewswire)
• Be prepared to discuss your impressions.

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Find the source of the information

• Use the media as a way to know WHAT is being
  talked about but dont draw conclusions from
  media or popular reports, always go to the
  ORIGINAL SOURCE usually a report of the study
  in a peer-reviewed journal.

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Heidis favorites nutrition news sites

• NutraIngredients
• http//www.nutraingredients.com/
• Science Daily
• http//www.sciencedaily.com/

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Scholarly vs. Popular magazines

• Scholarly journals present new, previously
  un-published research that includes bibliography,
  authors name and academic credentials. Articles
  go through a peer review process before
  publication.
• Popular magazines articles are written by staff
  writers (not experts), are often geared towards a
  general audience, and are not peer reviewed
  before publication.

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List of high impact peer-reviewed journals in
nutrition

• Journal of the American Dietetic Association
• American Journal of Clinical Nutrition
• Journal of Nutrition
• Journal of the American Medical Association
• Nutrition Reviews
• Annals of Nutrition
• Journal of Nutrition, Health and Aging
• Journal of Nutrition Education and Behavior
• International Journal of Obesity

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Refining a pubmed search

• Use limits effectively
• Use the related article link
• Use MeSH Terms
• Automatic search updates using My NCBI (National
  Center for Biotechnology Information)

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• Conduct a pubmed search on beta-carotene and
  sunburn
• Can you find the original publication from the
  news-report you reviewed on this topic?
• Have other research papers been published on this
  topic?

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Credible sources of nutrition information on the
internet

• Professional health organizations
• Government health agencies
• Volunteer health agencies
• Consumer groups

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Credible Professional Health Organizations

• American Dietetic Association www.eatright.org/nc
  nd.html
• Society for Nutrition Education
• www.sne.org
• American Medical Association
• www.ama-assn.org
• Federation of

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Credible Government health agencies

• Federal Trade Commission
• www.ftc.gov
• The U.S. Department of Heatlh and Human Services
  (DHHS)
• www.os.dhhs.gov
• The Food and Drug Administration
• www.fda.gov
• The U.S. Department of Agriculture (USDA)
• www.usda.gov
• National Institute of Healths Office of Dietary
  Supplements
• http//ods.od.nih.gov/

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Credible Volunteer health agencies

• American Cancer Society
• http//www.cancer.org/
• American Alzheimers Association
• http//www.alz.org/
• American Diabetes association
• http//www.diabetes.org
• American Heart Association
• http//www.americanheart.org

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Credible Reputable consumer groups

• The Better Business Bureau
• www.bbb.org
• The Consumers Union
• www.consumersunion.org
• The American Council on Science and Health
• www.acsh.org
• National Council Against Health Fraud
• www.ncahf.org

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Credible Universities

• Utah State University Extension
• http//extension.usu.edu/

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Questions to ask to assess the credibility of Web
sites (ADA position paper)
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• Critically review the following website
• DSM nutritional products
• http//www.dsm.com/en_US/html/dnp/home_dnp.htm
• Be prepared to share your impressions

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Current topics of controversy or confusion in
nutrition

• Vitamin D how much do I need?
• Whole grains what are they?
• Supplements to take or not to take?
• Glycemic index useful tool?
• Probiotics bacteria for breakfast?

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Vitamin D
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Current DRI (AI) for vitamin D for infants
through adults age 50 is 200 IU/day. The current
UL (upper limit) is 2000 IU.
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• Vitamin D Insufficiency May Be Present In
  Pediatric Patients With Low Bone Density
• June 2, 2008 Vitamin D insufficiency is common
  in adults and is emerging in the world of
  pediatrics. A mild degree of vitamin D
  deficiency, also known as vitamin D
  insufficiency, causes rickets in children and .
• Low Vitamin D Levels Appear Common In Healthy
  Children
• June 2, 2008 Many healthy infants and toddlers
  may have low levels of vitamin D, and about
  one-third of those appear to have some evidence
  of reduced bone mineral content on X-rays,
  according to a new .
• Current Vitamin D Recommendations Fraction Of
  Safe, Perhaps Essential Levels For Children
• May 28, 2008 The current recommended daily
  allowance of vitamin D for children is 200
  International Units, but new research reveals
  that children may need and can safely take
  ten-times that amount. According to a .
• No Association Found Between Vitamin D
  Concentration In Blood And Risk Of Prostate
  Cancer
• May 27, 2008 High vitamin D concentration in
  the blood is not associated with a reduced risk
  of prostate cancer, researchers report in a new
  article. Laboratory studies suggested that high
  doses of vitamin D may .
• Extra Vitamin D In Early Childhood Cuts Adult
  Diabetes Risk
• March 13, 2008 Vitamin D supplements in early
  childhood may ward off the development of type 1
  diabetes in later life, reveals new research.
  Type 1 diabetes is an autoimmune disorder, in
  which insulin producing

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• Age
• Dark skin melanonin
• Sunscreen
• Time of day
• Season of year
• Latitude of location

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How much sun exposure?

• 1 MED dose of UVB radiation (enough to cause a
  mild sunburn) 10,000 20,000 IU Vit D
• Caution melanoma, wrinkles?
• Suncreen decreases Vit D production by 95
• Recommendation unprotected sun exposure on arms,
  neck, face for 5-15 minutes between the hours of
  1-5 pm during the spring, summer, and fall on
  most days for lighter skinned individuals is
  enough. After that time, apply sunscreen.

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Points to remember

• You cant get enough vitamin D from food alone.
• If you arent in the sun, or if dont effectively
  make Vit D when in the sun, you need a supplement
  (vitamin D3 cholecalciferol).
• Most experts agree a dose of 2000 IU is save and
  prudent for most.
• The only way to know your vitamin D status, is to
  have your physician check your 25 OH D2 (25
  hydroxyvitamin D) levels.

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Whole-grains
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http//www.wholegrainscouncil.org/
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Definition Whole grains

• Whole grains or foods made from them contain all
  the essential parts and naturally-occurring
  nutrients of the entire grain seed. If the grain
  has been processed (e.g., cracked, crushed,
  rolled, extruded, and/or cooked), the food
  product should deliver approximately the same
  rich balance of nutrients that are found in the
  original grain seed.

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http//en.wikipedia.org/wiki/Whole_grain

• Whole grains are cereal grains that retain the
  bran and germ as well as the endosperm, in
  contrast to refined grains, which retain only the
  endosperm. Whole-meal products are made from
  whole-grain flour.
• Common whole-grain products include oatmeal,
  popcorn, brown rice, whole-wheat flour, sprouted
  grains, and whole-wheat bread. Common
  refined-grain products include white rice, white
  bread, hominy, and pasta (although whole-grain
  varieties of pasta are available).

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List of whole grains

• Amaranth
• Barley
• Buckwheat
• Corn, including whole cornmeal and popcorn
• Millet
• Oats, including oatmeal
• Rice, both brown rice and colored rice
• Rye
• Sorghum (also called milo)
• Wheat, including varieties such as spelt, emmer,
  farro, einkorn, Kamut, durum and forms such as
  bulgur, cracked wheat and wheatberries
• Wild rice

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Why whole-grains?
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Although it is difficult to separate the
protective properties of whole grains from
dietary fiber and other components, the disease
protection seen from whole grains in prospective
epidemiological studies far exceeds the
protection from isolated nutrients and
phytochemicals in whole grains.
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• High in fiber ? SCFA in gut
• High in vitamins and minerals
• High in antioxidants
• High in other phytochemicals with known
  protective properties
• Lower Glycemic Index ? mediates insulin response

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How much do you need?

• The Dietary Guidelines for Americans, released in
  January 2005, recommend that all adults eat at
  least half their grains as whole grains that's
  at least 3 to 5 servings of whole grains.
• MyPyramid emphasizes whole grains

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Whats a serving?

• 16 grams of whole grains 1 serving
• 1 slice 100 whole grain break
• ½ cup brown rice
• 1 cup 1005 whole grain ready to eat cereal
• Every product with the Whole Grain Stamp contains
  at least half a serving (8g) of whole grains.

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Learn about whole WHITE wheat at the following
website http//www.wholegrainscouncil.org/whole-
grains-101/whole-white-wheat-faq Be prepared to
share your impressions
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Dietary supplements to take or not to take?
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http//consensus.nih.gov/2006/2006MultivitaminMine
ralSOS028main.htm
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Are MVM safe?

• Some ingredients in common MVM can produce
  adverse effects in certain people
• Beta-carotene and smokers
• Vitamin A and women
• Vitamin E as alpha-tocopherol
• DSHEA
• No pre-market approval required
• Self-regulated industry

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http//www.usp.org/USPVerified/dietarySupplements/
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Conclusion from NIH report

• Finally, the present evidence is insufficient to
  recommend either for or against the use of MVMs
  by the American public to prevent chronic
  disease. The resolution of this important issue
  will require advances in research and improved
  communication and collaboration among scientists,
  health care providers, patients, the
  pharmaceutical and supplement industries, and the
  public.

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POSITION STATEMENT It is the position of the
American Dietetic Association (ADA) that the best
nutritional strategy for promoting optimal health
and reducing the risk of chronic disease is to
wisely choose a wide variety of foods. Additional
nutrients from fortified foods and/or supplements
can help some people meet their nutritional needs
as specified by science-based nutrition standards
such as the Dietary Reference Intakes.
http//www.eatright.org/ada/files/fort.pdf
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Glycemic index
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http//www.glycemicindex.com/
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Glycemic response to carbohydrate

• Glycemic index the increase in blood glucose
  level over the baseline level during a 2-hour
  period for a defined amount of carbohydrate
  (usually 50 g) compared with the same amount of
  carbohydrate in a reference foods.
• Reference food typically white bread or glucose.
• Glycemic load the weighted average glycemic
  index of individual foods - GI multiplied by the
  dietary carbohydrate content.

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(a) Glucose
(reference food)
(b) Low glycemic index
(c) Fasting baseline
Blood glucose (mg/dL)
Hours
Glucose meal
Fig. 4-9, p. 83
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Ludwig et al. 2002 Jama
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Ludwig et al. 2002 Jama
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GI/GL categories
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GI controversy

• Foods can have different GI values as a result of
  ripeness, variety and processing.
• Intra-individual variation.
• The GI of a food eaten alone is different than
  the GI of the same food eaten with other foods.
• Standard test portions of foods used to determine
  GI are NOT usual portions.
• Low GI foods are not necessarily nutrient dense
  foods. Low GI does not healthy

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Factors known to influence glycemic index of a
food

• Fiber content
• Ripeness
• Type of carbohydrate
• Fat content of food
• Acid content of food
• Physical form of food ? processing etc.

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The good and the bad

• High GI, the good
• Better absorbed during exercise
• Facilitates greater glycogen storage following
  exercise
• Easy to consume given high kcal requirements

• High GI, the bad
• Cancer
• CVD
• Diabetes
• Overweight/obesity

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Ludwig et al. 2002 Jama
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Probiotics bacteria for breakfast?
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• Find a recent news report on priobiotics
• Conduct a pubmed search to identify original
  research on probiotics
• Look for a good review or meta-analysis
• Review this information
• Provide a critical analysis to the question
  Should probiotics be included in a healthy,
  balanced diet?

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