Episode 9: Nutritional Deficiencies and Dietary Supplements–Part 2 - a podcast by Dr. Robert Gaston, DVM - OneVetMed Podcast Host and Veterinarian

 
Episode 9: Nutritional Deficiencies and Dietary Supplements - Part 2Answering the questions about use of nutritional supplements:
How do we recognize/suspect the need?When should we use nutritional supplements?

 In order to better recognize and understand nutritional deficiency, it helps to review some basics of nutritional research

Methods: Experimental and observational study used to identify deficiency syndromesOften begun with the observation that certain foods influenced active disease processes

Limes used to prevent and treat scurvyEfforts directed toward identifying the beneficial substance(s) in those foods.
The primary focus of the early research was on vitamins 

Philosophy of Nutritional Scientists: Synthetic Reproduction of ‘Active’ IngredientsEarly research failed to recognize the chemical complexity of foods


Assumed that foods are simple mixtures of a few easily identified chemical constituents, which, through modern chemistry, can be easily reproduced 

Nutritional Research: Defining Nutrient Deficiencies(introduced this idea in episode 2 when describing how “essential” nutrients are identified for pet food.)Defining disease syndromes of nutrient deficiency relies on the total exclusion of a single nutrient, such as a vitamin, over short-term.
The manipulated diet produces the classical signs of disease associated with the absence of that nutrient. 

Understanding nutritional studiesObservational (dietary intake)

Diets containing large amounts of foods high in β-carotene (yielding high blood levels of β-carotene) have been associated with decreased risk of cardiovascular disease and several types of cancerIntervention trials (supplementation)

Different vitamin sources affect outcomes of clinical studiesSupplementation trials may yield contradictory results
Example: Synthetic β-carotene supplementation 

Nutritional Research-The Key to Understanding ‘Conflicting’ ResultsThe Case Against Vitamins Wall Street Journal March 20, 2006 p. R1, R3




http://www.mythyroid.com/documents/WSJVitamins.pdfhttp://online.wsj.com/article/SB114235146814497776.html

Prevalence - 70% of households buy vitamins$7 Billion spent on vitamins in 2005


RationaleBoost immune system
Protect heartDecrease risk of cancer


Results“May be doing more harm than good”
Detrimental effectsCancer promotion
Increased risk of heart failureLast year, Johns Hopkins University researchers in Baltimore published a shocking finding. After reviewing the data from 19 vitamin E clinical trials of more than 135,000 people, the analysis showed high doses of vitamin E (greater than 400 IUs) increased a person's risk for dying during the study period by 4%. Taking the vitamin E with other vitamins and minerals resulted in a 6% higher risk of dying.

Since the analysis was published, another study of about 9,500 patients evaluated long-term use of 400 IUs of vitamin E daily. The study didn't show any statistically meaningful differences between vitamin users in terms of cancer, heart attacks or stroke, but the vitamin E takers had a 13% higher risk for heart failure."The psyche of the U.S. population is that a nutraceutical can't be harmful and might be helpful, so why not take it?"says Dr. Klein."That thinking is just not correct.


What is going on?“Nobody knows why high doses of vitamins taken as pills might cause harm”
“What is clear, however, is the important role a healthful diet plays in preventing illness”The critical difference is that vitamin complexes and phytochemicals found in food are fundamentally different than isolated pharmaceutical doses of vitamins.


 Observation vs. Intervention: Detrimental Effects of Synthetic Beta Carotene

β-carotene initially appeared to be the associated link between lowered cancer...

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