Your Daily Dose of D

If you've been hearing about vitamin D a lot lately, you're not alone!  Researchers have long known the important role that vitamin D plays in calcium absorption and calcium balance and that diseases such as rickets, osteomalacia and osteoporosis were caused by a deficiency in vitamin D.  More recently however, vitamin D has become a hot nutrition topic as researchers are finding links between a deficiency and many prominent diseases including cancer (breast, colon, prostate), obesity, cardiovascular disease and chronic inflammation (arthritis, diabetes, multiple sclerosis).

Am I at risk of deficiency?

Data from the National Health and Nutrition Examination Survey (NHANES) revealed that in 2001-2006, approximately 33% of the population was either deficient in vitamin D or at risk of becoming deficient. Vitamin D deficiency is diagnosed by a blood test which measures the amount of serum 25-hydroxyvitamin D. Currently, the target level is set at 30ng/mL, but there is a lot of debate among doctors, researchers, dietitians and others in the medical field to raise the target to 50ng/mL. Those most at risk of vitamin D deficiency are older, non-white females and those with minimal exposure to the sun.

How much vitamin D do I need?

The current Recommended Dietary Allowance (RDA) for vitamin D is 10 mcg for infants and 15 mcg for children and adults. Women who are breastfeeding need 19 mcg per day. Vitamin D is sometimes also expressed as International Units (IU).  A daily intake of 400 IU is recommended for adults. Keep in mind that the RDA was set based solely on intake from food or supplements and does not assume intake from the sun.

How do I get vitamin D?

 

1. Sunlight – One form of vitamin D that the body synthesizes is found on our skin. However, this form is inactive until it is exposed to UV rays. The time of day, cloud cover and latitude can affect the amount of sunlight absorbed. Some research suggests that only 5-15 minutes between the hours of 10 a.m. and 3 p.m. during the spring, summer and fall may be effective and safe for people with skin that is prone to burning. Brief exposures to the sun are thought to equal about 5 mcg of vitamin D.
2. Diet – Consuming foods that are high in vitamin D can help prevent deficiency. Key food sources include fatty fish such as salmon (1 oz = 3.5 mcg), canned tuna (3 oz = 4 mcg), egg yolks (1 yolk = 1 mcg), beef liver (3 oz = 1 mcg), and irradiated mushrooms (½ cup = 1 mcg). Many fortified foods such as milk (1 c = 3 mcg), cereal (1 c = 1 mcg) and orange juice (1 c = 2.5 mcg) are also good sources.
   
3. Supplements – A daily multivitamin or supplement is another way to ensure you are getting enough vitamin D and they can be purchased without a prescription. Look for one that provides around 10-15 mcg or 200 IU of vitamin D3.

   

 

Healthfully Yours,

Meghan

Electrolyte Essentials

Let's talk electrolytes, people! Since starting my new job at the hospital, I've discovered that most people don't know what they are, what they do in the body or which foods they are found in. I figured my patients weren't alone, so I decided to share the exciting world of electrolytes with my faithful readers as well!

What is an electrolyte?
An electrolyte is a substance that, when dissolved in water, will become positively or negatively charged. They play key roles in our physiology and metabolism and even the slighted changes in their concentrations can wreak havoc on our bodies! Electrolytes include sodium, calcium, chloride, bicarbonate, potassium, magnesium and phosphate. Since sodium (Na+) and potassium (K+) are the two major electrolytes in the body, I'm going to focus on them.

Where are they in our body?

Sodium is found primarily in our extracellular fluid or the fluid that is outside of our cells. Potassium on the other hand is mainly found in the intracellular fluid, which is the fluid contained inside our cells (duh). The balance or concentration between these two is so important, that there is actually a “pump” in our body specifically to keep them where they are supposed to be.


Fluid compartments, electrolytes and the Na/K pump.

What do they do?
Think of potassium and sodium as partners, working together in three key functions:

1. Maintaining fluid balance between the extracellular and the intracellular compartments.
2. Participating in neuromuscular activities, including heart rhythm.
3. Maintaining pH or acid-base balance.

What are the key sources?
The majority of the sodium we consume is in the form of sodium chloride, or table salt. Sodium is naturally found in some protein sources, whereas fruits, vegetables and grains contain little to none. Processed foods (i.e. canned foods, lunch meats, frozen dinners) contain a lot of sodium for flavor and preservation.

Key sources of potassium are basically the opposite of sodium. Potassium is found mainly in fresh fruits and vegetables with bananas, potatoes and spinach being among the richest sources. Dairy products are often high in potassium as is fresh meat.

How much do I need?

Now that you know the key sources of these electrolytes, it should not surprise you that the majority of people consume too much sodium and not enough potassium. 

The dietary reference intake (DRI) of sodium for healthy adults is 2300mg per day, which is about 1 teaspoon of table salt! Those with heart conditions, diabetes or hypertension should limit their intake to less than 1500mg per day, which quite honestly, is nearly impossible to do in today's world of convenience foods. The minimum requirements for sodium are estimated to be as low as 200mg per day.


One serving of this product contains 1050mg of sodium! Compare that to the DRI!

The dietary reference intake for potassium for healthy adults is 4700mg per day, so better get snacking on those fruits and veggies! To give you a reference point, one banana has about 400mg.

How do I know if I am in balance?

Provided you are in good health, your body will naturally regulate the concentration and balance of electrolytes with fluid gains and losses.

And this brings me to one of my biggest pet peeves: Gatorade!

Compare the 40mg of potassium to the 400mg in a banana! What's the point?

Unless you are doing cardio for over an hour, working out in extreme heat or are vomiting or have diarrhea, there is no need for Gatorade or any other electrolyte replacement drink! Just drink water!

Healthfully Yours,

Meghan