Vitamin D’s relationship with sunlight is known across most of the world. In fact, in many places, it is known as the vitamin of the sun. The sunshine vitamin.
However, strictly speaking, Vitamin D is not truly a vitamin. Some authors recognize it as a hormone instead. That’s because vitamins are organic compounds that the individual must ingest.
They are not synthesized by the body. However, vitamin D production is possible through a process involving exposure to sunlight. So, it can, in fact, be considered a hormone.
Indeed, the primary natural source of vitamin D is solar exposure. But for most people, it is not enough, especially depending on where we live. In many cases, a supplemental and robust dietary intake is also necessary. However, very few foods contain enough vitamin D, and many of them are not frequently consumed.
This is one of the main reasons why vitamin D deficiency has taken on epidemic proportions. Without notice, there are many vitamin D deficient people in many countries around the world. And in most cases, they have symptoms and have no idea what’s the cause.
So, let us dive into the topic of vitamin D and see how it contributes to our health. We are also covering vitamin D deficiency, its symptoms, food sources, and other means to fix it.
What is vitamin D
Vitamin D has been regarded for years as the “cure-all” formula for many diseases. This may be a hype, but the truth is that its role in the human body is impressively varied. It is important for the immune system and cancer therapeutics. Also, it has been identified as a hormone, as stated above.
Vitamin D is not a single substance, and this is where some people get confused. It’s a group of steroid or fat-soluble substances. The most common varieties in foods are cholecalciferol and ergocalciferol. What we know as vitamin D2 is ergocalciferol.
Vitamin D3 is the same as cholecalciferol. The only difference between them is a double bond and a methyl group in vitamin D2. In other words, they are almost the same thing.
However, they are initially inactive and goes through the liver and the kidneys to activate. The active metabolite of vitamin D is called calcitriol. This variant is the one that binds to vitamin D receptors in the cell. When it does, calcitriol modulates gene expression depending on the type of cell.
That’s why we will see so many benefits of vitamin D. It’s because each cell activates their own machinery, depending on their functions (1).
Benefits of vitamin D
There are many health benefits related to vitamin D. It would aid the absorption of nutrients, calcium, magnesium, and phosphorus. That would ensure your immune system and your bones.
It prevents fragile bones and fractures as well as muscle weakness. Vitamin D would also regulate blood pressure and reduce stress and muscle tension.
This vitamin is a great aid for the body to distinguish cells one from another. This characteristic helps with insulin secretion. It also prevents abnormal cell growth in cancer. Moreover, immune system cells will get reasonable improvement.
Respiratory infections and other diseases such as asthma are also improved. And it helps to prevent multiple sclerosis, which is less common in the tropics. All we need is the right blood levels of vitamin D.
There are also benefits to your aesthetics because it will make your skin and hair look better. And if you combine that with a nice suntan, it will definitely make you look great.
So, we encourage you to leave the car once in a while. You will save some money on gas if you start walking a bit. Receive your daily dose of vitamin D, and don’t stop getting these wonderful benefits. They are all free, just a stride away.
Now, let us evaluate some of these vitamin D benefits, one by one (2):
1) Vitamin D fights disease
Vitamin D plays an essential regulatory role in the homeostasis of calcium and phosphorus. It also has a vital role in the modulation of the immune response.
As noted above, vitamin D binds to a specific receptor, called calcitriol receptor or VDR. It can be found in various cells of the immune system. For example, dendritic cells, macrophages, T cells, and B lymphocytes.
In the framework of immune function, Vitamin D can increase the antimicrobial effects of white blood cells. Monocytes and macrophages increase their capacity for phagocytosis and chemotaxis. They also speed up the synthesis of antimicrobial peptides. As such, adequate Vitamin D levels are crucial in the control of infections.
In fact, Vitamin D is required to activate the immune apparatus. Without it, T cells cannot react to a serious infection (3).
2) Vitamin D improves prostate health
The prevalence of prostate cancer is lower in countries with more sun exposure. This is apparently because they have higher levels of vitamin D (4). Moreover, many studies report that people with low vitamin D have a higher risk. It also has an important role in prostate cancer progression.
According to some randomized clinical trials, vitamin D supplements can slow down cancer progression (5). One step further, we even have a meta-analysis of several clinical studies with the same conclusion. It appears that higher vitamin D levels can improve survival and reduce cancer progression (6).
The exact mechanism by which vitamin D improves prostate health is not known. However, it may have to do with the anti-inflammatory role of this vitamin. It inhibits a series of cytokines and inflammatory pathways. Prostate cancer feeds off inflammation. Thus, vitamin D is probably creating a direct obstacle in the process of growth (7).
However, if we want this particular improvement in prostate health, we should aim for “normal” levels. Not very high levels.
According to research, having low levels can trigger prostate issues. But very high levels can increase the risk, too. Thus, what we need is to have appropriate levels of vitamin D (7). That’s why we will also describe below how much vitamin D do you really need.
3) Vitamin D reduces depression
Depression is a mood disorder characterized by pervasive feelings of sadness. It also features irritability, discomfort, impotence, frustration, unhappiness, and guilt.
These symptoms may be transient or permanent. Depression is typically accompanied by anxiety. It causes a partial or total inability to enjoy events of everyday life.
Unfortunately, a host of recent observational studies suggest a connection between Vitamin D and depression. As a steroid hormone, vitamin D plays a crucial role in a wide range of bodily processes. These include gene signaling involved the synthesis of mood-altering neurotransmitters. For example, dopamine and serotonin.
Since vitamin D is essential to modulate brain chemistry, it is associated with neurological features. Patients with vitamin D deficiency sometimes do not have physical but mental health problems.
They feel depressed, and sometimes very tired or anxious. Alzheimer’s disease is also more prevalent in people with low vitamin D levels. Thus, the association is clear. What we need to understand further is the exact mechanism (8).
4) Vitamin D benefits bone health
Bones are living organs that require constant regeneration. Bone remodeling is the process through which the body reabsorbs old bone tissue and replaces it with new and healthy bone.
Vitamin D helps the body achieve and maintain healthy levels of calcium and phosphorous. It directly contributes to calcium absorption. Thus, by modulating the absorption and excretion rates, Vitamin D plays a pivotal role in bone remodeling.
Calcium and vitamin D are inseparable allies. When the body experiences a long-term deficit of Vitamin D, these processes are interrupted. Bone remodeling breaks down, and various bone diseases may begin to manifest.
Bone loss, also known as osteoporosis, is one such disease. It may result in bones that are more fragile and significantly less resistant to trauma. They are also exceedingly prone to suffering fractures and microfractures.
It’s a common concern in older adults, and especially in women’s health after 50. However, men will also have osteoporosis if they have low levels of vitamin D.
Osteoporosis is a particularly insidious condition. It does not manifest any outward symptoms until the loss of bone mass is severe. Fractures begin to appear, and then it’s too late.
The most frequently observed fractures in these patients are vertebral, hip, and wrist fractures. Hip fractures are particularly important because they invariably require surgical intervention. Also, they significantly diminish the patient’s quality of life.
Therefore, it is important to consume enough vitamin D in conjunction with calcium. This will ensure proper absorption levels and maintain healthy bones. The main goal is to reduce the risk of osteoporosis, especially in seniors (9).
5) Vitamin D boosts weight loss
Impressively, vitamin D has also been linked with obesity and weight loss. Studies show that levels of vitamin D are inversely associated with obesity. In other words, obese people are usually vitamin D deficient. That’s why obesity is often considered a risk factor of vitamin D deficiency.
However, some studies have also evaluated vitamin D supplements to aid weight loss. They have reported that using these supplements facilitates weight loss. Vitamin D status is apparently associated with weight loss success. In other words, if your vitamin D levels are normal, you are more likely to lose weight.
Still, the results of the clinical trials are not always the same. Some studies report there’s no significant change. Thus, the association and the application in the real world remain to be seen. In the meantime, we can use vitamin D supplements and foods to complement our weight-loss efforts (10).
Vitamin D deficiency
Several clinical trials report that the prevalence of many diseases shows specific geographical variations. They are more common in certain parts of the world. Specifically, in higher latitudes, where less sunlight is absorbed.
That’s the case of certain types of cancers, inflammatory bowel disease, and multiple sclerosis. Other diseases include rheumatoid arthritis, type 1 diabetes, and osteoporosis.
Even patients with Alzheimer’s disease tend to have low levels of vitamin D. These observations have led us to believe that vitamin D insufficiency could be involved. And other studies have confirmed this suspicion.
Vitamin D has two primary functions in the organism:
- Calcium, magnesium and phosphorus homeostasis
- Modulation of the immune response
Thus, the consequences of a deficit tend to be of great clinical significance. Therefore, it is vital that we inform ourselves about the potential symptoms of low Vitamin D.
The most relevant symptoms of vitamin D deficiency include (2):
- Bone health problems: Vitamin D fosters calcium into our bloodstream, and it’s essential for bone metabolism. This is why vitamin D deficiency often causes bone loss. Bone density is an indication of how strong your bones are. It is also known as mineral density. People with low vitamin D would have low scores, making them susceptible to fractures.
- Rickets: Vitamin D deficiency is associated with low calcium levels in the blood. When this happens, young infants can experience convulsions and tetany. As time passes, these patients feel muscle weakness. Children also develop a protuberant abdomen. When sustained for a long time, it can cause deformities in the skeletal system as well.
- Recurrent infections: One of the most common symptoms is the vulnerability to illness and infections. Because of its role in the immune system, a deficiency can cause more infections. They can also be more severe than usual. The most common infections are those from the respiratory tract. They can be a simple flu or even pneumonia.
- Tiredness and low energy: It can be caused by many reasons, including vitamin D deficiency. As noted earlier, it can cause muscle weakness. Thus, an important sign in infants is a reduction in their activity levels and movements. In adults, many studies say that vitamin D deficiency can cause chronic fatigue. In many cases, vitamin D supplementation can fix this problem.
Vitamin D deficiency symptoms tend to be very vague and unspecific. We can start feeling deep pain and sensitivity, described as “in the bones,” and muscle fatigue. Even high blood pressure may be involved. These symptoms will get worse with time as the deficiency becomes worse. We don’t usually see a severe deficiency, but it’s not impossible.
Food sources of vitamin D
What can you do if you have experienced one of these vitamin D deficiency symptoms? Having just one of them is not an unequivocal sign you need vitamin D. However, it is a good idea to visit your doctor and tell him your concerns.
Many countries around the world have cases of vitamin D deficiency. Especially in Europe, Canada, and places away from the Equator. This is because sun exposure is one of the ways for your own body to synthesize this vitamin. But if you want to take a natural approach, don’t forget to protect yourself from overexposure.
You can also consider several food sources to increase your vitamin D intake. For example (2):
- Fatty fish: It is a reliable source of natural vitamin D. One of our favorite is halibut, which contains 932 IU of vitamin D for every 3 ounces. Salmon is another option, and it has 647 IU of vitamin D for 3 ounces.
- Cod liver oil: If you’re not using fatty fish on a regular basis, you can also benefit from cod liver oil. It has omega 3 fatty acids, vitamin D, and vitamin A. Only one tablespoon will give you around 450 IU of vitamin D.
- Eggs: Eating eggs with their yolk does not raise cholesterol levels, as some people may think. One cup of boiled eggs has up to 120 IU of vitamin D.
- Orange juice: Another vitamin D-filled breakfast food is orange juice. It has plenty of vitamin C, but also vitamin D. You can get around 100 IU for each cup.
- Fortified foods: In many countries, health authorities fortify cereals and dairy with vitamin D. One clear example is milk, which has plenty of calcium and also vitamin D when fortified. Even skimmed milk can have sufficient vitamin D. One cup has around 400 IU, and cheese has a similar proportion (11).
Vitamin D supplements are also a convenient way to deal with vitamin D deficiency. People who rather stay indoors, those who live in countries away from the equator, and anyone with vitamin D deficiency can take these dietary supplements.
They have been tested to solve vitamin D deficiency symptoms rather quickly, and they are safe to use. So, keep close communication with your doctor. Try not to stay indoors for too long, unless there’s a public health restriction going on, as in the current coronavirus pandemics.
How much vitamin D do you need?
It is true we can have a hard time figuring out a vitamin D deficiency. But it’s also true it’s easy to correct.
Walking under the sun every day is an effective way for us to get our daily vitamin D. Even obese people can benefit from this approach. Moreover, they would also get a really good cardiovascular benefit as a plus.
Also, the elderly and their propensity to fractures and falls can benefit from daily walking. They will get more hip and leg strength to prevent falling. Also, natural vitamin D to boost their whole system.
Through sunlight, 10 to 20 minutes of exposure usually give you enough vitamin D for the day. But what if you are living in a country with little sunlight or cannot go out for some reason. If that’s the case, you need a combination of diet and vitamin D supplements. And you need to know how much vitamin D you need every day.
The recommended daily intake is different for infants, children and adults, and seniors (2).
- Infants up to 1-year-old should have 300 IU of vitamin D every day. This initially comes from the mother’s breast milk. After a few months, babies can also eat fortified foods according to their age. There are liquid supplements, too.
- After 1 year up to 60 years old, you should have at least 600 IU of vitamin D. Food sources above, and sun exposure can help achieve that amount. In many cases, supplements will be required.
- Older adults over 60 years old should have 800 to 1000 IU of vitamin D every day. This is due to a reduction in the absorption rate as we age. That’s why vitamin D supplements are often prescribed around this age.
But, can you get too much vitamin D? Sure, there’s also a problem if you have an overdose. Vitamin D is a fat-soluble vitamin. Unlike B vitamins and other water-soluble vitamins, it is not easily eliminated in the urine. Thus, it accumulates in the body, and a high dosage can cause these symptoms (12):
- Confusion and apathy
- Abdominal pain and vomiting
- Increased thirst and urination
Toxicity starts when you reach 150 ng/mL of vitamin D in the blood. This is excessive and very rare. That’s why the tolerable upper limit for vitamin D has been established depending on the age:
- Infants: Less than 1000 IU a day
- Children up to 8 years: Less than 2500 IU a day
- Children 9 years and older: Less than 4000 IU a day
The benefits of vitamin D consumption and the best way to obtain them are somewhat controversial. However, they do have important implications for human health.
Vitamin D increases musculoskeletal health and reduces the incidence of bone health disorders. Supplementation can be very important in some high-risk groups, especially in the elderly.
There is evidence that vitamin D has a significant influence on the development of cancer. Deficiency is associated with heart disease, autoimmune processes, and infections. However, this evidence, although highly suggestive, is not yet robust enough. Thus, we can’t really draw any conclusions that establish a causal relationship.
Nutritional vitamin D status has gained importance in recent years, as it becomes more prevalent. Given the known effects, the current evidence suggests the need to raise the daily recommendations for dietary intake in adults. It also recommends the use of supplements to boost serum levels in high-risk groups further.