FN 225: Nutrition
Tamberly Powell, M.S., R.D.
Health Professions Division
Lane Community College
There is an EXAM this week DUE Thursday
There is an Exam 3 Study Guide posted in week 6 of moodle.
If you do not meet the exam deadline, as of
the following Monday, you may
take a makeup exam at the Instructional Testing Lab on the LCC Main Campus (CENTER
311). Students taking this exam in the Testing Lab are allowed
to use only ONE 3 x 5 notecard
1. How can you apply the information given in either the lecture this week or the local food resource?
(about cancer) at the end of Chapter 8 of our text. What
is one thing you read that is interesting to you? How can you
apply this information to your lifestyle?
LECTURE 7A: Vitamins & Minerals- part 1
Use this information to start filling out the lecture outline for chapter 7 & 8.
A vitamin is defined as an essential non-caloric organic nutrient needed in tiny amounts in the diet. As you learned in Week 1, vitamins are organic and DO have calories, but they don't have calories for us because we don't make the enzymes we'd need to break vitamins apart to release the energy. So that's what I mean by non-caloric. There would be very little energy there for us anyway- GRAMS of starch, sugar and fat give us a lot more energy than MILLIGRAMS of vitamin C. And we need that vitamin C for important functions in the body.
A mineral is defined as an essential non-caloric inorganic nutrient also needed in tiny amounts in the diet.
Vitamins can be divided into 2 categories:
Minerals are absorbed directly into blood and are always water-soluble. Examples of minerals include iron, calcium, zinc, magnesium, potassium, sodium, chloride, fluoride, manganese, phosphorus and selenium.
Minerals and water-soluble vitamins are absorbed directly into the blood. Fat-soluble vitamins are absorbed into the lymph.
You saw the above image earlier in the term. It shows why vitamins are organic (contain carbon to carbon bonds) and minerals are inorganic.
Looking at the Ingredient list for Honey Nut Chex cereal, which ingredients are:
|Minerals are different than vitamins because they are INorganic, therefore they don't have calories. Also minerals are
always absorbed directly into the blood.
Vitamin A and vitamin C are both organic. But Vitamin A is a fat-soluble vitamin so it is absorbed into the lymph, and travels with a carrier and is stored.
Vitamin C is a water-soluble vitamin so it is absorbed directly into the blood, travels without a carrier and is not stored.
Plants get vitamins by making them because they need them to function. Many of the vitamins that plants make are actually antioxidant pigments that they make to help them with photosynthesis. And each plant has its own set of pigments that it needs. A plant making orange carrots needs carotenes while a plant making cream-colored parsnips needs flavones.
Antioxidants in Photosynthesis and Human Nutrition, Demmig-Adams, Barbara; Adams, III, William W. Science; 12/13/2002, p2149, 5p. The harnessing of solar energy by photosynthesis depends on a safety valve that effectively eliminates hazardous excess energy and prevents oxidative damage to the plant cells. Many of the compounds that protect plant cells also protect human cells and have a role in human nutrition.
Vitamins can be made in the body in 2 ways. One way is from precursors, which are something that can be changed into an active vitamin. For example, niacin can be made from the amino acid tryptophan.
|Retinol (the active form of Vitamin. A) can be made from beta-carotene in plant food.|
|Vitamin D can be made when ultraviolet light in sunlight
strikes cholesterol in the skin. So cholesterol, which our body
can make, is a precursor for vitamin D. These children in the
country of Georgia (near Russia) are making vitamin D.
|A second way our body can make
vitamins is by letting good bacteria live within us since bacteria in
our intestinal tract can make vitamin K and also biotin and pantothenic
acid. Do you see on the list above what kind of nutrients biotin
and pantothenic acid are?
Probiotics and Prebiotics- more information on how bacteria in the gut may be beneficial.
|So now we're ready to move on to THE NUTRI-CHARTS
in the lecture outline.
These charts take sort of a "Three Bears" approach to vitamins and minerals as I have always loved their story. Of the three bowls of porridge Goldilocks came upon, one was too hot, one was too cold and one was just right.
So we'll look at what happens when there's too much of a nutrient, too little of a nutrient and just the right amount of a nutrient.
Involved in FLUID
& ELECTROLYTE BALANCE
A pale yellow urine indicates that the body probably has enough water to accomplish these tasks. See image below to determine your hydration based on urine color.
We are bombarded with choices when it comes to ways to stay hydrated, but keep in mind many of these choices are loaded with sugar and void of any nutrients. Look at those labels, and remember you can never go wrong with good ole' water!
What are electrolytes? Electrolytes are electrically charged particles called ions.
What are ions? When mineral (or other) salts dissolve in water, they separate into single, charged particles known as ions.
Important electrolytes include sodium (Na), potassium (K), chloride (Cl) and phosphorus (P). Can you find each of those 4 on the Periodic Table below?
Below is a Short Video that discusses Electrolytes
Here is a link to the above video: http://youtu.be/aELPrWzixeU
Sodium- Na The major positively charged electrolyte in the extracellular fluid (outside of cells)
As the NUTRI-CHART says, sodium is part of a sodium potassium pump that helps regulate fluid and electrolyte balance. This "pump" helps keep the correct amount of water INside cells by pumping electrolytes. Without this water, cells collapse and can't function. Here is an animation of this pump and how it works.
The glucose transporter that allows glucose to enter
cells, also requires sodium.
Too much sodium in the body can contribute to hypertension if a person is among the perhaps 5% of people with hypertension who are salt sensitive, although some say the figure is higher. However, whether high-sodium diets actually cause hypertension is still under debate. Many experts believe that a high-sodium/low-potassium diet is the biggest risk factor for hypertension.
Sodium may also cause calcium excretion in some people which can impact bone loss, but like hypertension research is not conclusive on this topic.
Potassium- K The major positively charged electrolyte in the intracellular fluid (inside of cells)
Many Americans do not get the recommended amount of potassium (4700mg per day). This is always a nutrient students report being low in after analyzing their diets using the SuperTracker. One way to increase your potassium intake is to eat more whole foods like fruits, vegetables, legumes, whole grains, and even dairy! Eight ounces of yogurt has more potassium than a banana. And potatoes are one of the best sources of potassium, beating out bananas as well. One medium baked potato has more than 1,000mg of potassium (see figure below).
Potassium helps keep the correct amount of water OUTside cells, by being part of the sodium/potassium "pump". Like sodium potassium also involved in nerve response to stimuli and muscle contraction.
Too little potassium in the body can be caused by abuse of what can be called the 3Ps.
Chloride- Cl Is a negatively charged electrolyte in extracellular fluid.
Chloride is obtained almost exclusively from table salt (sodium chloride). It is involved in fluid balance, is part of hydrochloric acid in the stomach, assists with the transmission of nerve impulses, and also works with white blood cells to help kill bacteria.
As discussed above too much salt may result in hypertension, but there is no other toxicity symptoms for chloride. Because of the high sodium intake of Americans most people consume more than enough chloride.
Phosphorus- P The major negatively charged electrolyte in the intracellular fluid.
Like the previous electrolytes discussed above, phosphorus helps maintain proper fluid balance, but it also has many more roles in the body. It is part of the mineral complex of bone so it plays a critical role in bone formation. It plays a key role in creating energy for our bodies since it is a primary component of ATP. It also is a part of DNA, RNA, phospholipids, and lipoproteins.
Phosphorus deficiencies are rare as phosphorus is widespread in foods, and is in high amounts in foods that contain protein. Milk, meat and eggs are all good sources (see figure below).
NUTRI-CHART 2 lists the Nutrients Involved that can be ANTIOXIDANTS.
During oxidation free radicals (atoms with unpaired electrons) are formed, and too many free radicals can cause serious damage to our cells.
Remember when you saw the little animated "movie" about covalent bonding earlier in the term? Unpaired electrons are "anxious". They go hunting for electrons to complete their outer shell. Unpaired electrons can grab from where they shouldn't, which can damage cells.
Antioxidants seem to be able to "scavenge & quench" free radicals & may offer some protection against cancer and effects of aging. The image below demonstrates this.Next we will discuss which nutrients act as antioxidants. Take a look at how these charts are organized. The column on the left shows the nutrient.
Keep in mind studies showing benefits of antioxidants have been done on antioxidants in foods, not antioxidants in supplements.
Then the next column describes a little of what happens in the body when there's TOO MUCH of that nutrient in the body.
The next column describes a little of what happens in the body when there's TOO LITTLE of that nutrient in the body.
The next column describes a little of what happens in the body when there's JUST the RIGHT amount of that nutrient in the body
Beta-carotene is not an essential nutrient, but instead is considered a phytochemical, and is a provitamin found in many fruits and vegetables. A provitamin is an inactive form of a vitamin that the body must convert to an active form. Our body converts beta carotene to the active form of Vitamin A. The body changes beta carotene slowly to retinol, so TOO MUCH beta-carotene is not toxic. Sometimes people get very enthusiastic about beta carotene rich foods (pumpkin, sweet potatoes, spinach, kale, and carrots) and they may get excess carotene, but it doesn't have toxic effects. Their skin may turn slightly orange (as seen on the right in the image below), but it isn't dangerous.
|Since beta carotene is not
considered an essential nutrient, and there is no RDA set, there are no
known deficiency symptoms for beta carotene. However, carotenoids
are associated with a decreased risk for cancer so TOO LITTLE beta-carotene in the diet/body may elevate
JUST the RIGHT amount of beta-carotene can be changed in the body to retinol and then it can perform the functions of vitamin A.
Beta-carotene has functions as an antioxidant in the body that retinol cannot accomplish. It's antioxidant functions help the immune system to fight disease, protect skin from the damage of UV rays, and protects eyes from age-related vision impairment.
|Vitamin E- a fat
Vitamin E is widespread in foods from plant sources (see figure below). Nuts, seeds, soybeans, and some vegetables like avocados, as well as plant oils (safflower, sunflower, canola and soybean) are all good sources. Animal and dairy products are poor sources of Vitamin E. Also, keep in mind Vitamin E is destroyed with heat so processed and fast foods contain little Vitamin E.
TOO MUCH vitamin E can increase the effects of
anticoagulant medication, including aspirin, risking uncontrolled
bleeding. As with most nutrients, more is not necessarily better, and
research has shown an association between high supplement intake and
increased risk for heart failure, prostate cancer and premature
|Vitamin C- a water
Unlike Vitamin E, Vitamin C must be consumed on a regular basis since it is water soluble and any excess is excreted rather than stored. Fresh fruits and vegetables are going to be the best sources of Vitamin C (see figure below). Vitamin C can be lost in foods with cooking. Steaming, microwaving and stir-frying are the best cooking methods to retain Vitamin C in foods.
TOO MUCH vitamin C in the body is usually not a problem
because excesses are excreted. However, with supplements taken in
can cause gastrointestinal distress.
|Selenium- a trace
Because selenium is a trace mineral, we need very little in the diet to support health. Selenium is stored in the tissues of animals, so you can find it in animal foods, but it is also found in the soil, so plants provide a source of selenium as well (see figure below).
TOO MUCH selenium does not result from eating foods, but can
happen with supplementation which can lead to liver damage.
|NUTRI-CHART 3 lists the Nutrients Involved in
Let's do the JUST RIGHT part of vitamin A first.
Vitamin A can be found in both plant and animal foods. Plant foods will be rich in the precursor to Vitamin A, beta carotene. The preformed Vitamin A will be rich in animal foods like beef and chicken liver, eggs, and whole-fat dairy products. Preformed Vitamin A can also be found in fortified reduced-fat milks, and some breakfast cereals (see figure below).
|When there is TOO LITTLE
vitamin A in the body, the cells make a dry, hard protein called
keratin (NOT the same thing as carotene, even though those words sound
a lot alike).
A person can become blind when keratin builds up in the cornea, shown below in the Bitot's spots. A person is more vulnerable to lung infections when deficient in vitamin A because keratin builds up preventing the lungs from expelling harmful substances. The eyes and lungs also suffer from vitamin A deficiency because epithelial cells lose their ability to produce mucus which causes the eye to become very dry, and the lungs more susceptible to disease.
And a person without enough vitamin A can become night blind because retinol is needed for the eye to see in dim light. (There are MANY other reasons a person might be night blind besides vitamin A deficiency.)
TOO MUCH vitamin A in the body is very toxic. Toxicity symptoms can develop after consuming only three to four times the RDA. Too much Vitamin A from foods is not common, but can occur with supplementation.
|The video below is optional and has some fun information on tomatoes. You don't need to watch this to fill in the lecture outline.|
|Video Clip: Supplies The Most Nutrients
approximately 10 minutes
END OF LECTURE 7A
NUTRI-CHARTS 4, 5 and 6 will be next week (Week 8)