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Archive for the ‘Vitamins of interest’ Category

Mind Your Vitamin D, Please!

In Nutrition Basics, Vitamins of interest on September 7, 2010 at 4:19 PM

Vitamin D is the all-star nutrient of 2010.   Most folks are already aware that getting enough calcium and vitamin D, through food and/or supplements, helps prevent osteoporosis.  Over the past few years, well-designed research studies have discovered additional health benefits for this vivacious vitamin, to include the prevention of cancer, heart disease, autoimmune disease, and even depression.   In response to all this convincing evidence, health agencies have questioned their previous guidelines for vitamin D intake, and plan to enlighten the public with their new recommendations very soon.   To aid your interpretation of these new intake guidelines,  I would like to review what is known about vitamin D up to this point and offer some suggestions to you.  In my professional opinion, most people would gain health benefits from minding their vitamin D intake.

1.  Vitamin D comes in two forms:  Vitamin D2 (ergocalciferol), which is produced by plants, and vitamin D3 (cholecalciferol), which is produced by select animals and human skin.   Your skin can produce vitamin D upon exposure to ultraviolet rays from the sun, specifically, UVB rays.  Sunscreens with an SPF of 8 or higher will hinder this process.

2.  Vitamin D is found naturally in very FEW foods, such as some fish (salmon, tuna, mackerel), egg yolks, and cod liver oil.

3. Foods such as cow’s milk, soy milk, rice milk, almond milk, yogurt, and orange juice, may be fortified with either vitamin D2 or D3.  Vegan foods, derived solely by plant sources, will contain the D2 variety.  However, D3 is more easily absorbed and used by the body, so if you are not a Vegan, consider fortified foods containing the D3 form of the vitamin.

4.  Vitamin D is included in most multivitamins and calcium supplements in concentrations of 50 IU to 1000 IU (international units).  As I write this, adequate intake recommendations for select individuals and age groups are being revised.  Currently, the daily upper tolerable limit is 2000 IU per day.  Based on the latest research, it is quite possible this upper level will be increased to 10,000 IU per day…  If you do take an oral supplement containing vitamin D, take it with your largest meal, as this allows for better absorption.  (FYI:  5 mcg=200 IU, in case your supplement reports micrograms instead of International Units)

5.  It has been found that many Americans have less than adequate blood levels of vitamin D.  The people most at risk for developing a vitamin D deficiency include people over age 55 (reduced ability to produce vitamin D from skin), people with limited sun exposure (such as the homebound or those living above the 42 degree N latitude), people with dark skin (melanin pigment inhibits vitamin D production upon sun exposure), and obese individuals (the vitamin is stored in fat cells and not released properly into circulation).

6.  Vitamin D aids in the absorption of calcium, helping to form and maintain strong bones.  A vitamin D deficiency can lead to weak bones as well as muscle weakness.

7.  More recently, Vitamin D has been found to enhance neuromuscular and immune function, and reduce inflammation throughout the body.  This action may provide protection against diseases such as multiple sclerosis (MS), rheumatoid arthritis, and lupus.  The research has revealed that people with higher vitamin D levels are less prone to such inflammatory, autoimmune illness.

8.  Vitamin D may also protect against both Type 1 diabetes (by decreasing inflammation and the autoimmune process) and Type 2 diabetes (by improving insulin sensitivity).  Research has shown that rates of both types of diabetes are lower in areas with greater amounts of sunlight and consumption of vitamin D rich fish. 

9. Vitamin D may prevent cancer by suppressing cell growth and blood-vessel formation that feed the tumor.  The research so far has been strongest for colorectal cancer, where subjects with higher blood levels of vitamin D were half as likely to develop the disease than those with lower levels.  In my opinion, it is still premature to advise the use of vitamin D supplements for the prevention of cancer.

10.  A heart attack may also be thrwarted by having adequate vitamin D circulating in your system.  Some research trials have shown that men with low levels of vitamin D (below 30 ng/mL) were twice as likely to have a heart attack than those with higher levels.  The same is true for high blood pressure.  At this point, it is believed that vitamin D may control the release of stress hormones that lead to high blood pressure and inflammation.

11.  Sunlight has long been known as a way to ward off Seasonal Affective Disorder, or SAD, a form of mild depression, that commonly strikes individuals living at northern latitudes during the winter months.  Sunlight promotes the release of serotonin, a mood-boosting hormone, lessening the symptoms of depression.  Therefore, it could also stand to reason that exposure to sunlight, and the resulting vitamin D production, may play a role in mood enhancement as well….we will have to wait and see where the research takes us on this one.

Now for the big question:  how do you know if you are getting enough Vitamin D?  Ask your doctor for a simple blood test.  The desirable blood level for overall health and disease prevention is > 30 ng/mL.   Levels below 15 ng/mL should instill immediate action in the form of supplementation.  Most often, this will require taking a 1000 IU or 2000 IU vitamin D3 pill daily.  Some doctors will prescribe “megadosing” for very low levels, which would entail taking 50,000 IU once a week for 8 weeks.  In this case, the excess is stored in body tissues and used as needed to maintain levels.

Other things you can do to keep your vitamin D levels up:

-expose your face and arms to direct sunlight (without sunscreen) for about 10 minutes 2x/week between 10AM-3PM

-Eat foods containing vitamin D:  3 oz sockeye salmon has about 800 IU; 3 oz. canned tuna 154 IU; 8 oz. of fortified milk, orange juice, or yogurt 100 IU; egg yolk 25 IU.  I suggest avoiding cod liver oil for a variety of reasons, but it does contain 1360 IU of vitamin D per tablespoon, should your levels be really, really low.

Should you have any questions once the new guidelines come out, please don’t hesitate to ask.  I am here to help you live a healthy, happy life 😉



Essential Supplements

In Nutrition Basics, Vitamins of interest on February 10, 2010 at 10:00 PM

The best way to get all the vitamins, minerals, and other nutrients you need is through eating a balanced, wholesome diet including all of the major food groups:  whole grains, fruit, vegetables, low-fat dairy, and protein from both plant (beans, nuts) and animal (meat, eggs) sources.  If you completely exclude any one of these groups for personal or religious reasons, you risk become deficient in a number of essential nutrients.  Therefore, it is important to determine if you should be taking a supplement or two.

What does a daily balanced diet look like, you ask?

-six servings of grains from bread, cereal, rice, pasta, etc.  Ideally, at least 3 of these servings should be from 100% whole grains—one serving equals a slice of bread, 1/2 cup pasta or rice, 1 oz. cereal.   And guess what popcorn lovers???  Three cups of popcorn counts as a serving of whole grain!  (just make sure you don’t minimize the health benefits by piling on too much salt and butter…)

-two to three servings of fruit–one serving would be a medium piece of fruit (size of tennis ball), 1/2 cup of berries or chopped melon, or 6 oz. of 100% fruit juice

-three to five servings of vegetables (more would be even better)—one serving equals 1 cup of raw, leafy vegetables (like salad) or 1/2 cup cooked or chopped vegetables.

-two to three servings of dairy foods such as milk, yogurt, and cheese—one serving is 1 cup milk/yogurt or 1 1/2 ounces of natural cheese.

-two to three servings of lean meat, poultry, fish, dry beans (lentils, black, kidney, etc…), eggs, or nuts—one serving equals 2-3 oz. meat (size of deck of cards).   One egg, 1/4 cup cottage cheese, 1/4 cup tuna, 1/2 cup cooked beans, 1 oz. nuts, or 2 Tbsp. peanut butter count as 1 oz. of meat.

Even if you try to eat all the major food groups regularly, you may still fall short if:

1.  your hectic lifestyle frequently keeps you from eating the recommended number of servings from each food group

2.  you are on a very low calorie weight loss diet (less than 1200 calories)

3.  you are elderly and not eating as much as you should

4.  you are a strict vegetarian, or vegan, who does not consume any animal products at all

5.  you are “lactose intolerant” and can’t drink milk or eat cheese & yogurt

6.  you are a woman of childbearing age who doesn’t get enough folate from fruits, vegetables, beans, and grains

7.  you are a “creature of habit” or a self-proclaimed “picky eater” who eats the same kinds of foods every day  (variety increases diet quality)

8.  you skip breakfast or lunch on a regular basis

It is probably safe to assume that most people do not eat the optimal amount of nutrients on a regular basis, and therefore, would benefit from taking a daily multivitamin.  It is wise for a pre-menopausal woman to take one containing iron.  Men and post-menopausal women should take a multi without iron—such as a “men’s formula” or “senior/silver” vitamin.   Most women should also take a separate calcium + vitamin D supplement to prevent bone loss–Calcium citrate formulations are most easily absorbed. Vitamin D is the “vitamin of the decade” and is now recommended for both men and women to prevent a variety of conditions above and beyond osteoporosis.  People who live in northern climates often are deficient in vitamin D due to limited sun exposure–our skin is capable of manufacturing this nutrient in response to ultaviolet light.  It is important to note that sunscreen inhibits this process, so if you live in a sunny climate but wear SPF religiously, you may need extra vitamin D supplementation as well.

The moral of the story?  Take a daily multivitamin–it doesn’t have to be anything fancy, just your basic “Centrum” or “One a Day” or generic store equivalent, tailored specifically for women, men, or seniors.  You should probably also add calcium citrate with Vitamin D—500-1500 mg calcium/day depending on whether or not you consume any dairy products or other calcium-fortified foods.  Adding a separate 1000 IU vitamin D if you live in northern latitudes(above the Mason-Dixon line) may benefit you as well. 

FYI:  Despite being a dietitian, I do not consume the recommended number of servings from all the major food groups on a regular basis either.  I take a daily women’s multi which has 800 IU of vitamin D and 450 mg calcium—and then supplement that with an extra 600 mg calcium and 400 IU vitamin D in a combined pill.  That way, I am getting the recommended 1000 IU vitamin D for northern latitude inhabitants and 1000 mg calcium for pre-menopausal women.  I also eat 1-2 dairy servings per day, which provides and extra 300-500 mg calcium for my bones 😉 

These are the only supplements I can comfortably recommend to the general population.  There are plenty of other supplements on the market that can be helpful in a given situation, but I cannot make such generalizations here without examining your individual food intake, lifestyle habits, etc.

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