Did you know that we have 13 vitamins (4 fat soluble and 9 water soluble) & 21 minerals (7 major and 14 traces) that our bodies need? Across the US severe deficiencies are not as common today but there are marginal in several. Many of the vitamins activate enzymes and some affect gene expression.
So what are the fat-soluble vitamins? A, E, D and K. Since they are not water soluble they have to be transported by chylomicrons to the liver and from the liver they are transported to tissues by proteins. The storage of most of these happens in the liver A, D, and K. E is store in the adipose (or fat) tissue.
Vitamin A's function has to do with vision. It can cause rhodopsin (night time blindness). It also deals with gene expression - it affects cell to cell communication, reproduction, the immune system and also bone growth. The cells of these systems require vitamin A to express genes for normal growth, immune competence and reproductive competence. Vitamin A deficiency in women can become keratinized and cause temporary sterility in females. If you see toxicity of this vitamin it is usually because of taking a supplement. We can safely take 5 to 10 times the recommended RDA and wont have any problems. Excess or toxicity can cause birth defect on babies in utero and can also cause you to turn yellow. Where can we get vitamin A from? liver, butter, egg yolks, orange colored vegetables, & dark green vegetables. Most of the vitamin found with the vegetables is in the provitamin form and only around 1/2 is turned into vitamin A.
Vitamin D, the sunshine vitamin!! (and again another fat soluble vitamin). What does Vitamin D do? It functions in calcium homeostasis. It also affects gene expression as well. Vitamin D regulates calcium absorption and storage. It stimulates gut cells to absorb Calcium from the gut, bone cells to deposit & mobilize Calcium into and out of the bone, and also stimulate the kidney cells to increase resorbtion from urine. A and D work together to effect the transcription of genes. Potassium effects translation. Where can we find vitamin D? There seems to be some discrepancy even amongst those following the RDA standards as to how much our body can make. Our bodies can synthesize somewhere in between 50 to 100% of the Vitamin D that we need. The exposure to sunlight utilizes cholesterol to the precursor molecule that will turn into vitamin D. If you are white skinned they say that we need between 5 to 30 minutes of sunlight per day between the hours of 10 a.m. and 3 p.m. with NO sunscreen two days per week. If you are darker skinned, you need closer to the 30 minutes 2 times per week. There are other factors - where you are in the world, how close you are to the equator, what season of the year it is! They all play an impact into how much sunshine you need. But guess it comes down to, make sure you get some time OUTSIDE :) That is a good excuse to play or go for a walk, take your kids to the park, go for a hike, garden. Make that some YOU time. So let's say you can only get 50% of Vitamin D from the sun - where are you supposed to get the rest? You could choose to eat fortified milk or orange juice (if you eat processed foods) or it can also be found in oily fish and mackerel. What are signs of deficiency? Soft bones! no not osteoporosis (which is brittle bones). This one can cause your bones to get soft. In children, this is called rickets and in adults it is caused osteomalacia. As the body gets heavier and heavier, and if you are not getting the vitamin D that you need,the legs will start to bow out due to the lack of mineralization. If someone gets rickets, they say that it is irreversible and that you will have it your entire life. They say that we should not use sunscreen over SPF 15, this is enough to protect the skin but it still lets some sun into and onto the body. So how much is toxic? 4000 IU per day, that is considered the toxic upper limit. It can cause calcium deposits into the heart. (On a side note, how do I personally use vitamin D : we do use sunshine only in the spring, summer and fall months when we can get out in the sunshine. So we rely solely on sunshine for part of the year. In the winter however, when the sun is far away, and there are not as many opportunities to get out and it is cold - we supplement. I and the kids take 1 to 2,000 IU per day. If someone starts to get sick then we up it. I only give whoever is in need the extra for a few days and then we go back to normal. My husband who does not get out in the sun as much and is deficient is taking 2000 IU per day year round. That is my personal philosophy and also one that our PCP supports)
Vitamin E, functions as one of the 8 antioxidants. This vitamin is capable of quenching oxygen and nitrogen based radicals. The radicals can be toxic and can damage the double bonds in membrane phospholipids, the DNA/RNA and proteins and enzymes. Deficiency of this vitamin is rare as vitamin E is found widely in most foods like wheat germ, whole grains, and green plants. Clinical signs of deficiency would be red blood cells rupturing and eye degeneration in premies. In adult females, it can lead to fibrocystic breast disease and for both male and females nighttime leg cramps. They say that there is not a toxicity level. (On a side note on this one, i think if you have issues with fat absorption or GI issues that it is possible to be deficient on this. On the last vitamin and mineral panel they ran on my son, he was deficient in E. It is not because he doesn't eat a wide variety of foods, he does. He was on a whole food supplement for awhile. He is done for now but we will be retesting in december to see where he stands on those things that he was deficient on. Kids are showing signs of the fact that they are having GI issues again so who knows what this will turn out)
Vitamin Ks function is blood coagulation. The liver synthesizes the proteins necessary for blood clotting and the enzymes require vitamin K as a coenzyme (that which is going to activate it) So vitamin K, can activate the enzyme G-glutamyl carboxylase and also affects gene expression. Possible sources of vitamin K, are from intestinal bacteria (you can get around 50% there). Some dietary sources are dark leafy greens and also liver. Deficiency is not common and the causes of it are usually not nutritional. When you take antibiotics, it kills the healthy bacteria in your gut or from fat malabsorption. Premies can be born with a sterile gut. Symptoms of deficiency would be prolonged bleeding. It is considered very toxic so the feds tell us that we should avoid supplements for this.
Our body can have medium to high body stores of fat soluble vitamins. Deficiency and toxicity would develop slowly. Deficiency could take months to years. Toxicity over a long duration of time.
One thing I will say, the recurring theme through a lot of the vitamins is leafy greens! Leafy green supply so many different vitamins and minerals, if you are not currently eating them this is a important one to get in there. If you have not tried them, think about trying green smoothies
Well that is probably WAY more information than you wanted to know. I have all the water soluble vitamins to do but had probably get back to my actual studies.
Maybe with a little luck I will be able to post some Thanksgiving treats the week of Thanksgiving!!