Vitamin A, Potassium, and Iron: The essential nutrients that are popular and easy to obtain from diet yet missed out.

This particular blog is to raise awareness of the roles of potassium, vitamin A, and iron in promoting growth in children and health in general population.

First, let’s talk about potassium-my favorite enemy- because I have to plan my meals around it every time I cook. Most adults need 4700 mg of potassium a day, although this number changes drastically throughout lifespan. For example, a lactating woman needs 5100 mg of potassium a day. The recommended amount of potassium also depends on how much sweat you lose throughout the day: if you work out in the field, belong to a construction work group, or simply train for a marathon, you’ll need more than 4700 mg of potassium a day. In general, in the United States, only 2% of the population meet the Recommended Daily Intake (RDI for short). In deed, potassium is one nutrient that is required in the largest amount, followed by calcium (1000-1200 mg) and sodium (500-2300 mg). In order to get 4700 mg of potassium, people need to be mindful about what they ingest. 

Anyway, why do we care about potassium intake? Well…Potassium just happens to be one of the key electrolytes that participate in say…blood pressure regulation, cardiovascular system, muscle growth, nerve impulses, bone metabolism, fluid balance (think kidneys and dialysis). You actually can get yourself killed if you lose too much electrolytes without replacing it-which may happen in a short period like 3-4 hours during a marathon (of course, it is an extreme case).

So, if you have high blood pressure and you do not want to take medications, you may want to try it through dieting and exercise. When you exercise, you train your blood vessels to be more plastic, making the blood pumping an easier job on the vessels (after all, high blood pressure is called the silent killer because it weakens your blood vessels slowly…very slowly…and once the vessels lose its plasticity, you’re seeing different numbers in your annual blood test). When you diet, you cut the salt down to 1500 mg a day, or start drinking decaf tea and coffee, or both, and that may improve your blood pressure by 5-10 points (that’s a big sacrifice though). However, your blood pressure will be improved tremendously once you eat enough potassium (it helps stabilize and improve your blood pressure). My approach will be making sure you get at least 4700 mg of potassium daily for 1 month, check blood pressure twice a week, before I do more modification to the diet.

Say if you’re a swimmer trying to achieve the fastest time ever…and yet you keep getting the cramps in your legs, that may not be a coincidence. You may need to get more potassium. Besides, if some of you are sprinters or power lifter, you need to know potassium is your friend because it helps transform glucose to glycogen (stored only in 2 places- liver and muscle) for immediate use. Say you’ve an elder in your family who is suffering muscle atrophy due to age that impairs daily living functions (such as weak grip strength), you may want to add more potassium along with special designed resistant training. If you happen to have issue with the cardiovascular system, you will want to consume more potassium. Say you have a 5 year old boy or girl and he or she stands short compared to other kids even though your height isn’t that short off compare to those kids’ parents? You may want to check out your child’s potassium level, since your kid may have retarded bone growth due to potassium deficiency.

Enough said. So we see potassium participates in major systems of the human anatomy which makes sense why it is required in the largest amount compared to other nutrient requirement. Right?

However, not everyone needs to worship potassium. There are certain population groups that must limit potassium, because it could kill them if overdosed. People with kidney failure are sensitive to potassium. These people are the ones that must painstakingly count potassium just like diabetic patients must count their carbohydrates.

Now, we can’t talk about muscle growth and bone growth especially among children without touching on vitamin A and iron. These two topics will have their own blogs later, but I need to emphasize that they play a big role in growth. In fact, according to the National Nutrition Institute of Vietnam, there are 50% of Vietnamese women classified as anemia due to iron deficiency (there are other types of anemia due to some other deficiency or genetics). Among pregnant women in the South East Vietnam, including those living in Ho Chi Minh City, a total of 24% suffer anemia. The percent of pregnant women in other regions is even higher: 45% of the North mountainous region and 44% for the Central of Vietnam and Nothern Plains.

What happens when these pregnant women suffer anemia? For one thing, they face higher risk during child labor due to blood loss. For another, they’re weak so they may not even have the strength to go through natural labor process. Last but not least, their newborns probably have higher risk of being one of those low birth weight infants. And, it just happens that low birth weight infants tend to have vitamin A deficiency, which usually causes growth retardation if not corrected. Unfortunately, most people in Vietnam have yet been familiar with prenatal nutrition and child nutrition. So…I hope the next generation will be more mindful about their health and that of their loved ones.

Okay, let’s look at some food sources that have rich content of vitamin A, potassium, and iron.

1/ Beet greens or amaranth leaves


The leafy green parts of the beet plant that are discarded and tossed aside are actually the most nutritious green thing. When it comes to potassium, nothing surpasses the beet greens, seriously. It has the highest concentration of potassium with the highest nutrient density (meaning besides being the best source of potassium, it also offers high concentration of other nutrient in the same serving).

Per 150 g of cooked beet greens, we get 1300 mg of potassium or 40% of RDI, 15% of iron RDI, 62% vitamin A RDI, 50% of daily value of vitamin C, 35% of vitamin B2 RDI, and a whooping 800% of vitamin K, on top of just 45 kcal. That is, my friend, nutrient dense food. Do watch out for the amount of vitamin k you have in your diet, though. I mean vitamin K is fat soluble, so if you consume the food with say 5 mL of oil, your body will be able to absorb and the excess part will be stored. If you overdose yourself day after day with vitamin K, you most likely will experience brain damage or liver malfunction. I’ll talk more about it in vitamin K blog.

2/ The red beet

The beet greens are the best source of potassium and their roots-the beets- also have high potassium level. Every 150-g-portion provides us 65 kcal, with 13% daily value of potassium and 8% RDI of iron.

3/ Bok choy (pak choy):


It’s my favorite vegetable because it is my main source of calcium, decent source of potassium and folate, excellent source of vitamin A, and a good source of iron. A portion of 200 grams provides about 44% daily value of vitamin A, 20% daily value of potassium, 12% of iron, 18% of folate, 18% of calcium and only 24 kcal for all that. And…it’s very easy to find at low cost compared to the beet greens.

4/ Sweet potato

purple sweet

My latest fascination is actually Okinawa (purple) sweet potato (pictured) I eat at least 400 g of these sweeties a day (I don’t eat rice or other starches- they’re treats only).

An average portion of 200 grams provides 180 kcal, 950 mg Potassium (about 27% daily value), 29% daily value of vitamin B7 (aka BIOTIN, aka vitamin H) for hair-skin-nail health, 35% vitamin B6, 35% vitamin B5, 18% vitamin B1, and 15% vitamin B2.

I honestly stick to only Okinawa sweet potato mainly because of its high concentration of antioxidants (another blog, another day) that is 3 times more active than the same type found in blueberries. Even when I don’t have access to these purple cuties, I’ll still keep regular sweet potatoes in my diet for the sake of my hair, nail, and skin health.

5/ Malabar spinach aka slippery spinach:


I remember playing with the berries of this plant when I was a kid. And stained purple juice on my shirt and finger nails used to drive my mother crazy. Good old days. Okay, a portion of 150 grams of cooked Malabar spinach gives us 20% daily value of potassium, 17% daily value of calcium, 8% daily value of iron, 260% of vitamin C, 200% daily value of vitamin A, and 50% RDI of folate (Did I mention folate- also known as folic acid or B 9- was important in preventing neural tube defect-one of the many possible birth defects?)

6/ Spinach


Similar to Malabar spinach, the original humble spinach is also a great source for potassium. A small portion of 150 grams (cooked) provides 20% RDI of potassium, 35% magnesium, 22% vitamin E, 60% folate, 95% vitamin A, 33% daily value of iron (beef? move over, cow), 20% calcium. However, I do not consume spinach regularly at all. Well, it’s because I am paranoid about kidney stones. Well, spinach has ridiculously high level of oxalate. So, if you do have a history with kidney stones or have weak kidneys, you should watch out of foods with high oxalate levels.

7/ Chrysanthemum garland leaves:


If you ever see these in the Asian market, run get them. You will not be disappointed of its flavor. A portion of 150 gram cooked leaves has 24% daily value of potassium, 30% iron, 270% RDI of vitamin K, 18% daily value of vitamin E, and 18% daily value of folate.

The BIG OLE NOTE: All vegetables contain vitamin C. Some of them contain great amount of vitamin C and iron. So what? The issue with iron from non-animal sources (aka non-heme iron) is that it is useless unless you consume it AT THE SAME TIME with vitamin C. Unfortunately, vitamin C is not stable to heat. That is the majority of it will be destroyed through heating. On top of that, whatever left behind will leak into the water (boiling/stewing) and if you throw the broth away, you will probably won’t get much vitamin C from your vegetable.

You can over come this shortcoming easily by getting your vitamin C from fruit sources, such as a kiwi, a slice of papaya, half of a guava, half of an orange, or a few slices of mango, so that you can get the iron from your vegetables. When I do have my boiled veggies, I drink all the broth and make a dipping sauce with a raw red chili pepper. That tiny red chili pepper provides 110 mg (more than enough). I am not a fan of fruit in whatever form because I want to limit fructose-a type of sugar and too much sugar will cause other issues (another blog about sugar once I’m done with the basic info about vitamins and minerals).


2 thoughts on “Vitamin A, Potassium, and Iron: The essential nutrients that are popular and easy to obtain from diet yet missed out.

    • Hello, sorry for the late reply. Here, the list of these vegetables in this blog are available in Vietnamese as following:
      1. Beet greens or amaranth leaf= rau dền
      2. Red beet = củ dền
      3. Bok choy (pak choy)= cải thìa
      4. Sweet potato = khoai lang
      5. Malabar spinach = rau mồng tơi
      6. Spinach = rau chân vịt or rau bina
      7. Chrysanthemum leaf = rau tần ô

      These vegetables are available almost year round if you live in the Central and South Vietnam. In the north, during the winter, you probably wanna switch to sweet potatoes, turnips (củ cải), broccoli (bông cải xanh), and pumpkins (bí đỏ or bí ngô).

      Số lượt thích

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