Exploring the sense and nonsense of food and health

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The Importance of Vitamin B12

Vitamin B12, a water-soluble  vitamin is stored and reused more efficiently that it does other water-soluble vitamins. A deficiency is therefore caused more by poor absorption rather than by a low intake alone.

A deficiency can cause pernicious anemia that is best treated by B12 injections instead of megadoses of vitamin B12 supplements or dietary means. Deficiencies are rare but there can be marginal vitamin B12 status, particularly in older adults and/or vegetarians who consume no animal products.

A deficiency also interferes with the maintenance of myelin  that coats the nerves, spinal cord, and brain. When the myelin degenerates, neurological symptoms of numbness and tingling, abnormalities in walking, memory loss, and disorientation occur. If not treated, this eventually causes paralysis and death.

FYI: Please do not take vitamin B12 supplements without getting your vitamin B12 levels checked. No toxic effects have been reported with excess intakes up to 100 ug/day but there is insufficient data to establish an Upper Tolerable Intake. The RDA for adults of all ages is  2.4 ug/day.



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Sweet Potatoes: Revisited


There is so much conflicting  information about carbohydrates  these days. The simple message is: Cut carbs, but wait- all carbohydrates are not equal. An example is easily shown between a comparison of a sweet potato with a white potato, both of which are common starchy vegetable choices.   A previous post shows us why nutrient density can be more important than simply noting just the calories and carbohydrate grams.


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The Hazards of Diet Supplements

We are a country obsessed with dietary supplements. Try taking them away and see how people resist the idea.  But do we need all those vitamins and minerals- sometimes, especially during key growth periods (pregnancy and childhood)?

So you think that just to be sure, you should take them as insurance against certain diseases. Maybe not. Sometimes excess is not the answer and may become harmful.  A famous example was a study that gave beta carotene  supplements(vitamin A) to smokers. The reason was that beta carotene was thought to be protective against lung cancer since it functions as an antioxidant. The result showed that there were more cases of lung cancer in the vitamin group than in those smokers given a placebo. Subsequent studies supported this finding.

What does the research say? You may be surprised.

Read the article HERE.




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Super Fortified : “Foods” or Supplements?

Should You Get your Nutrients from Super-fortified Foods?

The label on the orange juice container says “calcium added”. The water bottle label says “fortified with vitamin C”; the energy drink s is “fortified with 23 added vitamins and minerals.” Do you need all these extra nutrients ?

These foods may actually act like dietary supplements. If you eat nutritious unprocessed whole foods, you probably do not need fortified foods and even may go over the Tolerable Upper Intake Levels (UL).

The UL is a set of values that are well above the needs of everyone in the population and represents the highest amount of the nutrient that will not cause toxicity symptoms in the majority of healthy people. As intake rises above the UL so does the risk of adverse health effects.

To establish a UL, a specific adverse effect is considered. For example, for niacin, the ill effect is flushing, and for vitamin D it is calcium deposits in soft tissue or kidney damage. For vitamin C it is digestive disturbances. For some nutrients, these values represent intake from supplements alone; for some, intake from supplements and fortified foods, and for others, total intake from foods, fortified food, water and nonfood sources and supplements. For some nutrients, data are insufficient to establish a UL.



“In traditional foods, the amounts of nutrients are small and the way they are combined limits absorption, making the risk of consuming a toxic amount of a nutrient almost nonexistent. On the other hand, this risk rises from eating an excess of a supplement or excessive servings of super-fortified foods.”

Young children may be particularly at risk for toxicity. “A new report says that “millions of children are ingesting potentially unhealthy amounts” of vitamin A, zinc and niacin, with fortified breakfast cereals the leading source of the excessive intake because all three nutrients are added in amounts calculated for adults.”

“Outdated nutritional labeling rules and misleading marketing by food manufacturers who use high fortification levels to make their products appear more nutritious fuel this potential risk, according to the report by the Environmental Working Group (EWG), a Washington, D.C.-based health research and advocacy organization.”

For example, if you drank the recommended two to three liters of fluids as water fortified with vitamin C, niacin, vitamin E and vitamins B6 and B12, you would exceed the UL for these vitamins. Then add two cups of fortified breakfast cereal and two protein bars during the day, your risk of toxicity increases even more. In many of these products, you also could be getting a not so healthy dose of sugar. Should we be consuming super-fortified foods without a thought? I think not. For a previous post, click HERE.

Source: Lori A. Smolin, Mary B. Grosvenor, Nutrition: Science and Applications. Third Edition.

Source:  USA Today, Michele Healy, June 24, 2014.




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Bacteria Rule – How is That?

Bacteroides biacutis—one of many commensal ana...

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Our intestines are colonized by about 500 to 1,000 different species of what is referred to as “gut microbiota”.  What do all these microbes do?  Escherichia coli (not the harmful species 0157:H7) can help with water reabsorption and produce some of the vitamin K we need.  For the last few decades, scientists have developed what is known as “germ-free” mice; i.e. their intestines are sterile.  By using these species of mice, Jeffrey Gordon at Washington University School of Medicine in St. Louis discovered that a species of Bacteroides, a common inhabitant of human guts actually triggered intestinal cells to turn on or turn off some 100 of the 35,000 genes in the cell’s DNA.  Some of these genes helped the mice absorb and metabolize sugars and fats.  All in all, this particular Bacteroides species and probably others helped to regulate the calories the body obtains from food and stores as fat.  In other words, they may help regulate weight.

A recent study has strengthened this theory.  It suggests that the type of “bugs” in our intestines may influence whether we are lean or tend to being overweight.  Previous research has shown that heavier mice have a different gut bugs than leaner ones.  The obese mice have more of a bacteria called Firmicutes and fewer  Bacteroides (both of which reside in the human gut).  In normal mice, the situation is reversed.

Jeffrey Gordon and colleagues this time used human microbiota and injected germ-free mice with samples of human feces from which the bacteria then began to live in the guts of the mice.  Then the researchers began altering the diets of the mice.  When one group was fed a typical American diet, high in fat and sugars, they tended to gain weight and grow more Firmicutes gut bacteria and fewer Bacteroides.  When mice were fed a low-fat diet, the composition of the microbiota reversed and the animals stayed thin.  So if it remains true for humans when your gut bacteria contain more Firmicutes, your body may digest calories in a way that leads to more fat storage.  After the bacteria were transplanted from a lean human donor, the colonies in the mice had a high proportion of Bacteroides and a low content of Firmucutes.   But within 24 hours after the mice were switched to a high-sugar, high-fat diet, the proportions of the two species were reversed.  When identical twins were studied with different weights, the heavier twin had more Firmicutes colonies than the leaner one had.

Gut Bacteria and Vitamins

Now a new study published in Nature has separated gut bacteria into three major types to explain why the uptake of medicines and nutrients varies from person to person.  The study looked at the gut microbiota of 39 people from Europe, the U.S. and Japan and found that categories were not dependent on location, age, gender or body mass index.

Oluf Borbye Pedersen, professor of Health Sciences at the University of Copenhagen, said in a prepared statement.  “We may have uncovered a new “biological fingerprint” on the same level as blood types and tissue types”.  Having one of the three types, which are characterized by a dominate genus of bacterium – Bacteroides, Prevotella, or Ruminococcus, might play a large role in determining how you metabolize food to what vitamins your stomach is good at formulating (those in the Bacteroides group, for example, had a gut environment that was better at making vitamins B2, pantothenic acid, and biotin; those in the Prevotalla group had more B1 and folate-acid-making bacteria).

How can we control our own gut bacteria?  No one knows at the present time, but these studies shed light on the  complex causes of obesity and diet.

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