Vitamin D was first discovered in the 1920s. However, there’s something about it that most people don’t know. Ready for it? Vitamin D isn’t actually a vitamin. It is a pro-hormone. Its function in your body is to amplify the effects of the hormones that already are there.
Vitamin D, the hormone, is usually in an inactive state. However, the tissues and cells in our body are equipped with mechanisms that enable them to convert it into its active form. Our DNA contains 2,800 vitamin D binding sites.
What is Vitamin D?
Vitamin D is a vitamin that’s fat-soluble, unlike some others, and plays a key role in lots of health components. The main difference from other vitamins is that your body can synthesize a lot of it by simply exposing yourself to sunlight. This is why it’s also called the “sunshine vitamin.” Another interesting fact about it is that instead of just playing the role of a vitamin, it’s also a steroid hormone which is involved in bone health and weight management.
The conversion of vitamin D to its active form usually takes a two-step process, once you consume it. In the liver, it’s first converted into 25(OH)D or Calcidiol. This is the storage form. From there, it’s converted into 1,25(OH)2D, its active form, in the kidneys. Its work starts after this conversion. It involves communication with the cells in order for them both to control numerous functions in your body. These include boosting the immune health and altering the absorption of calcium.
The sun produces ultraviolet B (UVB) rays which provide energy that’s necessary for the production of vitamin D from the cholesterol in your body. Experts usually recommend that you expose yourself to sunlight twice per week, for periods of between 5 to 30 minutes. This will help you meet your body’s vitamin D needs. This period of exposure will vary according to age, body weight, and skin color.
Lack of vitamin D may lead to serious consequences. Sadly, there are millions all over the world who are deficient in this crucial vitamin. As a matter of fact, the US population is highly affected at 42 percent, according to a study released by Nutrition Research. Food sources may not be adequate since they are very few, and this complicates things even more.
If you live in a location where your exposure to the sun is limited or maybe your time limits you from stepping out to enjoy the sun, there are many ways through which you can still manage to meet your needs. Make sure to include foods rich in vitamin D into your daily diet. This way you will get what you need. You won’t even have to step outside.
History of Vitamin D
A deficiency of vitamin D causes rickets. This is a condition where softening of bones and consequently distortion occurs in children. In 1650, a British physician Francis Gilson described it in details. However, until recently, the cause of rickets had remained unknown. The first prescription for rickets was cod liver oil, in 1824. In 1924, however, Frederick Gowland Hopkins, a biochemist, suggested that conditions like rickets and scurvy could be caused by dietary factors.
Experiments were then conducted on puppies, beginning in 1919, just a few years after the initial findings. The results showed that rickets occurred when they were fed with bread and low-fat milk. Butterfat and cod liver oil was helpful in the prevention of rickets but it was, however, concluded that the presence of vitamin A was the main reason for this.
In 1922, Elmer Mccollum finally discovered vitamin D. Synthesis of vitamin D by sun exposure was still unknown at this time. In 1925, it was noted that a fat-soluble vitamin (D3) was produced when the compound 7-dehydrocholesterol was exposed to UV light. For his work and effort to fully understand the connection between sterols and vitamins, scientist, Adolf Windaus, was awarded the Nobel prize in 1928.
Today, we continue to discover more about vitamin D, its numerous functions and how it affects our health. Though bone health was what it was originally known for, scientists believe that Vitamin D is also involved in a range of other functions including weight management and immunity among others.
Benefits of Foods That Contain Vitamin D
- Helps Manage Weight. Sometimes, following a workout plan and a strict diet may not be enough to shed off the extra stubborn fat. That’s when you know it’s time to start eating lots and lots of foods rich in vitamin D. This will ensure that you are able to meet your daily vitamin needs. Research studies suggest that vitamin D is quite essential in weight loss. Research has also linked vitamin D deficiency to obesity.
A recent study has shown that low levels of vitamin D in the body are associated with high levels of body fat. On the other hand, another study revealed that a group of women whose vitamin D needs were met lost 7 more pounds than another group whose needs weren’t met. The study was conducted over a 1-year period.
What has remained unclear is whether vitamin D deficiency risks may be increased by obesity or if low vitamin D is caused by obesity. More research will be needed if the sophisticated role that vitamin D plays in controlling weight is to be understood.
- Boosts Brain Health. Brain health is also among the key functions of vitamin D, according to some studies. This is in addition to general body health. Other studies have gone even further, showing that conditions such as schizophrenia may be associated with low levels of vitamin D in the blood. Other conditions like insomnia, anxiety, depression and seasonal affective disorder may be influenced by how much vitamin D your body has.
Vitamin D has also a significant effect on the brain power. More vitamin D translates to more brain power. Poor performance in standardized exams, impaired decision making and difficulties with focus and attention are associated with low levels of vitamin D. This is according to the American Journal of Geriatric Psychiatry.
- May Help Prevent Cancer Formation. Just as what we eat plays a huge part in the risk of cancer and other chronic conditions, vitamin D levels also have a significant effect. However, the exact way the risk of cancer is associated with vitamin D remains a mystery because of limited research. Studies have revealed that certain types of cancer have a higher chance of occurring if one has vitamin D deficiency. These include colon, prostate and breast cancer.
Some aspects of cancer including cell death, cell growth, and cell differentiation are affected by vitamin D. This is according to Frontiers in Endocrinology. Reduced risk of occurrence of some types of cancer has been linked to vitamin D levels in the blood as well as exposure to the sun. As is highlighted by its importance, Vitamin D helps fight cancer.
- Strengthens Bones. Vitamin D’s effect on the density of your bones is among the most obvious benefits of this vitamin. Rickets, as a matter of fact, is the biggest symptom of Vitamin D deficiency. The condition, characterized by reduced mineral density in bones and bone abnormalities, usually affects children.
There are some other bone disorders that are on the rise these days. Osteoporosis is one of them. In addition to osteoporosis, vitamin D has also been linked to bone fractures as well as increased risk of falling in adults and lower bone mineral density. Rickets has become quite rare.
Consuming lots of vitamin D and increasing your exposure to the sun are just some of the ways through which you can maintain the health of your bones. They will also help reduce the risk of contracting these conditions. In addition to vitamin D, make sure that you are also taking lots of calcium, magnesium, phosphorus, and potassium. These will also help boost your bone health.
- Improves Immune Function. It’s quite easy and common among people to dismiss sniffles and sneezes as just part of the flu season. However, most people have no idea that low vitamin D levels have an impact on certain infections and immune problems. Cell replication is among the functions of vitamin D and it helps prevent infections like the cold and other autoimmune conditions.
Prolonged inflammations, which are the root causes of some serious diseases, can also be prevented by Vitamin D. Studies have revealed that vitamin D deficiency plays a crucial role in heart disease, cancer, and diabetes. Other inflammatory conditions include Lupus, inflammatory bowel disease, and rheumatoid arthritis.
How Do You Get Vitamin D?
We have already established that vitamin D is very important.
So how do you get enough of it?
There are two forms of this hormone:
- D2: 25 – hydroxyvitamin D.
- D3: 1.25 – dihydroxyvitamin D.
The human body requires D3. Some foods have it, or better yet you can just synthesize it by exposing yourself to sunlight.
Vitamin D and Vegetarians
Studies have revealed that omnivores, also known as lacto-ovo vegetarians, have a higher intake of vitamin D than vegans. The risk of getting too little of this vital vitamin is higher for anyone whose diet doesn’t include foods rich in vitamin D. This is especially true in places where there’s limited sunlight exposure.
If you choose to take the supplement D2 because you have low levels of vitamin D, you will need to take an increased dosage. However, if you want to take D3, a normal dosage will be fine since it’s more powerful than D2.
How Much Vitamin D Do You Need?
There are numerous studies with lots of different information that conflicts with each other. Some studies are really exact on the levels of vitamin D in the blood and they even go further to give the exact amounts of vitamins that one should have in the blood. According to the Institute of Medicine, optimal levels lie between 50nmol/l (20ng/ml) to 125nmol/l (50ng/ml). It’s important to continue taking in vitamin D until you get to the recommended blood level.
This would be wonderful if you had an exact number for your vitamin D blood levels. It’s not helpful, however, since only a few of us know this. Most of us also don’t want to have our blood drawn regularly in order to check our level.
It would make more sense to determine the level of Vitamin D intake that would get the population into the healthy range. For healthy adults, the vitamin D RDA is 600IU in the USA. The figure shoots up to 800 for people aged over 70. Evidence, however, shows that the higher number is beneficial since absorption of vitamin D is quite a problem for a lot of people. Malabsorption is another issue. Due to the trouble associated with Vitamin D absorption in some people, they would probably do better with lots of it.
Gut health is a particular problem for paleo. For absorption of vitamin D to happen, the gut has to have the ability to absorb dietary fats since Vitamin D is fat soluble. Some problems that may prevent the gut from absorbing vitamin D, especially in people who have tried paleo, include:
- Specific kinds of liver disease
- Cystic fibrosis
- Celiac disease
- Specific forms of ulcerative colitis
- Crohn’s disease
Since a lot of vitamin D is sucked up and hidden away in the fat, obese people need more vitamin D. They need approximately 40% more than people with normal weight. If people with normal weight have enough RDA, then obese people would need 840IU if under 70 years and 1120IU for those 70 years and above.
Getting enough vitamin D for your particular needs is crucial if you fall into one of these categories.
When to Take Vitamin D?
There exists an inverse relationship between melatonin and vitamin D. Melatonin is your sleep hormone. Taking vitamin D at night, therefore, doesn’t make too much sense. I have personally experienced this effect.
An experiment (n=1) which was conducted recently concluded that it’s best to take vitamin D in the morning. Taking the Vitamin D doses in the morning increases the number of hours you will sleep, deep sleep and REM after using a ZEO. The quality of sleep may plummet if you take the exact dosage at night.
While conducting biohacking experiments, I found the same results. Taking vitamin D in the morning resulted in great sleep while taking it at night resulted in restless nights.
Healthy sleep is invaluable in a busy world. Our sleep suffers if we fail to take the recommended amount of vitamin D. The importance of sleep cannot be underestimated if your job involves a lot of stress.
The amount and time for taking Vitamin D can be determined for other reasons. In a study conducted with patients suffering from chronic pain, it was found that Vitamin D helps ease the pain, helps with sleep and improves the general life quality. Having the correct amount of vitamin D may control inflammation, helps with poor mood, protects against cancer, heart disease and helps regulate the immune system. The majority of the population is deficient in Vitamin D and they don’t know how vitamins can help improve their lives.
Vitamin D and Sleep
Over half of the world population is Vitamin D deficient. As earlier stated, Vitamin D has a direct impact on the quality and amount of sleep. In an uncontrolled study, there was a big improvement in neurologic symptoms as well as sleep in participants who increased their vitamin D intake.
In yet another study involving 3,048 men who were aged 68 and above, the quality of sleep and vitamin D were observed. Researchers measured sleep efficiency, total sleep time and wake time and their frequency. Sleep efficiency is the total time spent in bed against time spent sleeping.
The results revealed that low quality of sleep was related to low Vitamin D levels. It was the same case with less than 5 hours of sleep per night and low scores in sleep efficiency.
Enough Vitamin D has other benefits too, including inflammation control and pain reduction.
Getting Vitamin D from Food
Some foods contain small amounts of vitamin D and unless you eat huge amounts frequently, they may not provide enough of these crucial vitamins. Sardines and salmons among other fish found in cold waters are some of the foods rich in vitamin D.
- Farm-raised salmon: 411IU per 6-OZ serving.
- Canned mackerel: 497IU per 6-oz serving.
- Herring: 364IU per 6-OZ serving
- Wild-caught salmon:1694IU per 6-oz serving.
Other fish also contain some amounts of vitamin D, though they are almost negligible. Eating wild-caught salmon each day (around 6 ounces) would guarantee you sufficient vitamin D from food. This might not be possible for a lot of people though. Most people will have to rely on sunlight and supplements in order to meet their daily needs.
Getting Vitamin D from Sunlight
We synthesize our own vitamin D from the sun. This happens when the rays of the sun hit our skin. Studies have revealed that 5-30 minutes of exposure is enough for a healthy adult to synthesize enough vitamin D. It’s usually best when the sun is high in the sky.
Exposure to the sun, while you have sunscreen on, doesn’t count since sunscreen blocks the rays of the sun from getting into your skin.
Getting Vitamin D from Supplements
Food alone cannot give sufficient Vitamin D to adults and it may not be possible for everyone to get enough exposure to sunlight, especially during winter when most people stay indoors. That’s why supplements are the only alternative.
Since Vitamin D is so rare and yet so important, Paleo recommends Vitamin D supplements. Eating a well-balanced diet doesn’t guarantee that you don’t need supplements.
How Much Is Too Much?
An issue about overdosing can only arise with supplements. Staying under the sun for long hours will not do you bad since the body has its own mechanism of stopping vitamin synthesis. It stops producing the vitamin once your needs are met. Getting dangerous amounts from food is not likely to happen unless you’re feeding on too much salmon.
With supplements, 4000IU units per day are set as the upper limit by the USDA, for healthy people aged above 9. This includes pregnant women. Sunshine provides up to 10000 IU daily. Some researchers have argued that this should be the limit. However, your body has the ability to automatically stop the synthesis of Vitamin D from sunshine if it’s too much for you. You need to be careful with supplements because they don’t come with guarantees.
Vitamin D Deficiency
Vitamin D deficiency is among the most common deficiencies. The risk varies in different people. Black people are at the highest risk percentage at 82.1 while Hispanics are at 69.2%. 41.6% is the global average. The elderly in the society are also at a higher risk of deficiency.
Certain diseases can also indicate that one has Vitamin D deficiency. A study showed that 96% of people who’ve had heart attacks have low vitamin D levels.
Due to the subtle nature of symptoms, vitamin D has been dubbed the silent epidemic. Symptoms may take long periods, maybe decades, to show.
Rickets is the most common symptom of Vitamin D deficiency. It’s mainly prevalent in developing countries, especially among children.
However, some foods were full of vitamin D back in the day, due to some measures in public health. This eliminated rickets from the societies in the west.
Fractures and increased falls among the elderly, osteoporosis and reduced mineral density have been linked to deficiency.
According to various studies, low levels of vitamin D increase the risk of cancer, heart disease, both types of diabetes and autoimmune diseases such as multiple sclerosis, just to name a few.
Vitamin D deficiency has also been associated with a higher risk of death from almost all sources.
It’s not yet clear if Vitamin D deficiency has anything to do with these diseases or whether people with low levels are just at a risk of getting them.
Magnesium, Vitamin A, and K2 Are Important Too
It’s important to always remember that nutrients don’t work alone.
Their functioning depends on each other and if you have a higher level of one in your body it may increase the need for another. Some researchers say that it’s important to synchronize vitamin K2 and vitamin A intake together, as well as supplement them with vitamin D3.
This is true for vitamin K2, also a fat-soluble vitamin which is quite rare just like Vitamin D. Most people don’t have sufficient amounts of this vitamin. Magnesium often lacks in our modern diets. It’s an important mineral that’s crucial for the Vitamin D in our body.
Here are a few Vitamin D interactions:
- Aluminum and Vitamin D. Most antacids contain aluminum. The intake of aluminum is usually increased by Vitamin D. If you have kidney disease, this interaction may cause problems. After taking vitamin D, wait for two hours before taking anti-acids. Alternatively, you can take antacids and then wait four hours before taking Vitamin D.
- Calcipotriene and Vitamin D. Vitamin D is quite similar to this drug, calcipotriene (Dovonex). Taking these two together may lead to severe side effects of calcipotriene (Dovonex). It would be best to avoid Vitamin D supplements while you’re using calcipotriene (Dovonex).
- Digoxin and Vitamin D. Absorption of calcium is helped by Vitamin D. Calcium may affect your heart. Digoxin makes your heart to beat stronger. Taking digoxin along with Vitamin D might lead to increased effects of digoxin (Lanoxin) which may cause an irregular heartbeat. Consult with your doctor if you need to take Vitamin D while also using digoxin (Lanxin).
- Diltiazem and Vitamin D. Calcium absorption is majorly dependent on Vitamin D. Diltiazem (Dilacor, Cardizem, Tiazac) also affects your heart. It’s important to avoid large amounts of vitamin D while taking diltiazem since it may reduce the effectiveness of the drug.
- Verapamil and Vitamin D. Vitamin D is a key player in the absorption of calcium, which affects the functioning of the human heart. Verapamil (calan, covera, isoptin) also has an effect on the heart. Avoid taking too much vitamin D if you’re using verapamil (calan, covera, isoptin).
- Water Pills and Vitamin D. As stated above, vitamin D assists the body in the absorption of calcium. On the other hand, water pills (thiazide diuretics) raise the levels of calcium in our bodies. Taking water pills (thiazide diuretics) along with Vitamin D may lead to abnormal levels of calcium in the body which may lead to severe side effects such as kidney problems. Some of these pills include hydrochlorothiazides (HydroDIURIL, Esidrix), chlorothiazide (Diuril), indapamide (Lozol), chlotharlidone (Hygroton) and metolazone (Zaroxolyn).
Top Vitamin D Foods
In a recently conducted nutrient survey, most respondents were concerned, and rightfully so, because they had low levels of vitamin D. Only 9% were aware that salmon contains Vitamin D, while 5% knew about fortified tofu. 22% were still searching for the most important vitamin in foods.
Below are some of the richest sources of this Vitamin D.
- Egg yolks
- Almond milk
- Pudding made with milk
- Orange juice
- Fortified tofu
- Beef or calf liver
- Shiitake mushrooms
- Wild-caught fish
- Breakfast cereals
- Canned fish
It’s safer to take vitamin D orally or through an injection into the muscle. Unless there’s too much intake, side effects aren’t usually experienced.
Headaches, dry mouth, loss of appetite, nausea, metallic taste, vomiting, fatigue, weakness, and sleeping are some of the side effects.
It might be unsafe to take more than 4000 units per day for extended periods of time. This is because it may cause very high calcium levels in the blood. However, vitamin D deficiency is treated by having high dosages for short periods. A healthcare provider should be present for the period of treatment.
Even though taking plenty of foods rich in vitamin D helps to lower the deficiency risks, exposure to sunlight is necessary, whenever possible. Supplements are also necessary, just to ensure that you are able to meet your daily needs. If you are deficient in vitamin D, see a doctor for the best treatment.
Vitamin D should be taken together with healthy fats to enhance its absorption since it’s fat soluble. These fats include extra virgin olive oil, grass-fed butter, ghee, coconut oil, nuts, and seeds.
It’s important to follow the prescribed dosages of supplements in order to avoid toxicity. Sunlight and dietary sources will not lead to toxicity. Toxicity may lead to symptoms such as nausea, vomiting, weakness and frequent urination.