Where vitamin D3 is found, what it’s for, and why it’s deficient.

Vitamin D3 is an essential nutrient that helps balance the calcium and phosphorus in bones. It plays a role in insulin secretion, the lining of blood vessels or endothelial function, cell creation and death (cell apoptosis), and the body’s defenses (immune system).

Often referred to as cholecalciferol because it is the active form found in the body, vitamin D3 has many health benefits for babies and adults.

It can be obtained through food, supplements in drops, capsules, and tablets, or produced naturally by sun exposure on bare skin.

There are many benefits and functions, which we will explain below.

What is Vitamin D3 and What Does It Do

It is a prohormone necessary for many human physiological processes. Vitamin D3 is fat-soluble (liposoluble) and its deficiency is associated with various diseases like rickets, coronary disease, cancer, and autoimmune diseases.

Its role is crucial in the body. Without it, calcium absorption is impaired, and blood cannot clot, along with other problems. There are many properties and benefits, so let’s look at what vitamin D3 is for:

• Assimilation and maintenance of calcium and phosphorus in the skeletal system, bones, and teeth.
• Blood coagulation.
• Stabilization of nerve impulse transmission.
• Controls calcium levels in the body to ensure they are appropriate. Calcium presence is necessary for transmitting electrical impulses to muscles.
• Monitors and supervises cell duplication and death.
• Regulates the immune system function.
• Ensures proper insulin function.
• Controls blood pressure and extracellular fluids through the renin system.

This type of vitamin helps maintain the correct calcium-phosphorus balance. By taking vitamin D3, bones maintain their quality, support body weight, remain flexible yet strong.

It is also essential to prevent infections and diseases. The immune system depends largely on the presence of vitamin D.

Moreover, since it participates in the cell life cycle, including cell birth, death, or apoptosis, a deficiency of vitamin D3 can lead to abnormal cell growth, which could develop into a tumor.

But let’s examine in more detail how it works…

Calcium and Vitamin D

Bone health is directly dependent on the calcium that accumulates in the skeletal system.

Vitamin D3 is related to calcium because it allows the mineral content in the foods we consume daily to be absorbed and incorporated into bones.

When there is a vitamin D deficiency, the body cannot produce calcitriol, the hormone that is active vitamin D. When there is a decrease in volume and a significant deficiency, it will be compensated by extracting calcium from the bones. As you can imagine, this is not good.

Taking calcium from the skeleton that is not absorbed through food causes weak and thin bones. Regeneration begins to slow, and bone damage stops repairing. In a short time, this can lead to osteoporosis.

People with calcium deficiencies are also more likely to experience bone fractures and fissures, as well as a reduction in bone thickness.

Hypertension

There is much scientific literature showing that vitamin D deficiency increases blood pressure. People with low skin exposure to solar radiation have higher values.

These low levels can be related to different pathologies or circumstances such as age, place of residence, or even race. People with dark skin are more likely to suffer from hypertension due to this deficiency.

In colder months when there is less solar radiation and reduced sun exposure, cases where blood pressure changes increase. Conversely, in the summer, it decreases.

This organic molecule regulates atrial natriuretic factor, and a vitamin D deficiency leads to secondary hyperparathyroidism when the parathyroid glands in the neck produce too much parathyroid hormone (PTH). This happens because calcium levels are low. And as we have already mentioned, the calcium levels in the body are directly influenced by the amount of vitamin D3 available.

All this —secondary hyperparathyroidism— leads to a higher predisposition to develop hypertension, myocardial fibrosis, and left ventricular hypertrophy.

It also triggers improper functioning of the renin-angiotensin system, which modulates blood pressure and plasma activity, resulting in what is known as hypertension.

A study called “Ultraviolet B and blood pressure” indicates that sun exposure reduces hypertension. However, although the evidence is moving in this direction, more studies are needed to truly confirm that vitamin D could effectively reduce hypertension in the general population.

Heart Health

There is also evidence that the risk of cardiovascular accidents is related to poor vitamin D levels in the body. Various observations show that people with coronary and heart-related diseases had deficient levels of this vitamin.

Furthermore, this is closely linked to hypertension cases, with very different percentages in normotensive individuals, meaning those with normal blood pressure.

In patients with chronic kidney failure, since they have a reduced ability to convert vitamin D into its active form, taking calcitriol or paricalcitol may be a solution.

To Boost Defenses

It acts on the cells that serve as the body’s defense. It works on lymphocytes, dendritic cells, and antigens, so the body’s response to infections is heightened. The immune system is better prepared to protect itself.

Several studies show that low vitamin D synthesis increases the risk of developing type 1 diabetes, Crohn’s disease, rheumatoid arthritis, and lupus.

Vitamin D3 for Babies and Children

Although there are different views, it is clear that it is very beneficial for young children and during the early stages of life. It prevents rickets and improves bone health.

Breast milk is the ideal food for the first six months. It contains all the minerals and nutrients a baby needs. In some cases, since sun exposure is rare to prevent skin damage from the sun, breastfeeding provides little D3. In these cases, it is recommended to include a vitamin D3 supplement for babies.

From the 6th month of life, the pediatrician may recommend introducing a dose of vitamin D at 400 IU/day until the first year. Infants who do not receive breast milk should take it, provided they drink less than 1 liter per day, according to the Spanish Pediatric Association (AEPED).

However, before starting to give it to your child, consult the pediatrician. They will provide the guidelines and instructions you should follow.

Vitamin D3 Deficiency

Although the signs of vitamin deficiency can sometimes be confused with other conditions, there are always symptoms when vitamin D3 deficiency appears. Here are some of them:

• Tiredness.
• Fatigue.
• Changes in mood.
• Restlessness.
• Poor sleep.
• Laziness.
• Low strength.
• Increased dental cavities.
• Inflammation and bleeding of gums.

There are also diseases associated with vitamin D deficiency over a prolonged period. These include:

• Arthritis.
• Cancer.
• Diabetes.
• Various cardiovascular diseases.
• Multiple sclerosis.
• Hypertension.
• Osteoporosis.
• Osteomalacia.
• Rickets.
• Increased periodontal discomfort and conditions.
• Alzheimer’s.
• Depression and other mental or neurological disorders.

For arthritis, having low vitamin D levels causes cartilage damage not to be repaired, so over time, osteoarthritis may develop.

In the case of cancer, the proliferation, creation, and death of cells are controlled by vitamin D. Inadequate levels force uncontrolled growth regulation, increasing the cases of tumors.

In diabetes, it affects glucose tolerance in the body, insulin production, and sensitivity to the substance. A decrease in insulin leads to a higher risk of developing diabetes mellitus.

Cardiovascular problems are related to calcium plaques in arteries and also with increased high blood pressure, as already mentioned.

Weakened bones are more prone to fractures and damage. The increase in osteoporosis is directly linked to calcium intake and its absorption. It is strongly related to low vitamin D levels, especially in women after menopause.

The lack of bone mineralization or osteomalacia is caused by vitamin D deficiency in adults. In children, rickets may occur.

Depression can occur in places with low sunlight or due to limited sun exposure to produce natural vitamin D. Other psychological disorders and neurological conditions, such as Alzheimer’s, can also emerge.

On a muscular level, there is evident deterioration. The person suffers from continuous muscle cramps, weakness, and lack of strength. This symptom is common in people who practice bodybuilding.

Where Vitamin D is Found

There are three easy ways to eliminate vitamin D deficiency:

1. Getting sun exposure with bare skin. The best way to obtain it.
2. Eating foods rich in vitamin D. It has poor absorption.
3. Treating with calcitriol to counteract calcium deficiency or adding supplements with vitamin D2. This is well absorbed.

Getting sun is good because the incidence of solar radiation on the skin activates the production of vitamin D naturally in the body. It is considered the best way to increase it. This is why countries with plenty of sun have a low percentage of people with vitamin D deficiency, whereas Nordic countries with limited sunlight during the year have a higher percentage of people with this deficiency.

Eating foods provides the basic form, though its absorption is limited. It is the least effective method.

Taking supplements is an alternative when not enough sun exposure is possible. The following steps happen after ingestion:

1. It will be hydroxylated in the liver to produce 25(OH) D.
2. Another hydroxylation occurs in the kidneys to circulate it in its active form as vitamin D3.

In cases where this is insufficient or difficult to follow, high-concentration vitamin D supplements can be used, such as 20,000 IU, 2,000 IU, 1,000 IU, etc.

Foods

• Chicken, beef, rabbit meat, etc.
• Fish such as herring, mackerel, salmon, sardines, tuna, and bonito.
• Shellfish.
• Salmon.
• Offal such as liver.
• Egg yolk.
• Milk.
• Yogurt.
• Cheese.
• Mushrooms.
• Eggs.

As mentioned, the best way to obtain vitamin D is by getting sun exposure for a few minutes, but it is also important to include foods containing vitamin D3 in your diet.

Meat and fish are excellent sources of this vitamin, as well as other vitamins, minerals, proteins, and amino acids.

It is important to vary the diet by alternating foods that contain vitamin D to avoid a deficiency of other essential nutrients.

What Benefits and Properties Does It Have?

• Boosts the body’s defenses.
• Regulates heart function.
• Strengthens bones.
• Prevents tooth deterioration.
• Regulates the nervous system.
• Establishes proper insulin levels in the blood.
• Prevents spikes and drops in blood pressure.

The benefits of vitamin D3 are incredible for human health. When a deficiency is detected, a series of symptoms can be found that, when addressed with a supplement or by adopting good dietary practices and controlled sun exposure, can be solved in just a few days.

Vitamin D3 and K2

The combination of these two vitamins has remarkable properties for health. While vitamin D3 enhances calcium absorption and regulates the cardiovascular and immune systems, vitamin K regulates blood clotting, with K2 promoting calcium distribution throughout the body.

Thus, taking vitamin D3 and K2 enhances their mutual benefits. Often, even if there is no D3 deficiency, if there is a lack of vitamin K2, calcium will not be distributed properly throughout the body, causing the same symptoms as a deficiency or lack of the mineral due to poor diet or a disorder that prevents its absorption.

Relationship with Testosterone

Some studies suggest that vitamin D3, K2, and testosterone are related. By regulating hormone synthesis, vitamin D can prevent testosterone formation when the body enters a deficient state, and since testosterone plays a crucial role in reproductive health, a lack of vitamin D could lead to a series of reproductive disorders, such as erectile dysfunction, low sperm motility, and even polycystic ovaries.

Next, we will address the most common questions about this vitamin.

Vitamin D3 or Cholecalciferol

In reality, these refer to the same substance or compound in the body. When referring to vitamin D3 or cholecalciferol, we are talking about its active form in the body.

Depending on the publication or specialist, both names may be used to refer to the same compound, that is, C₂₇H₄₄O.

Does It Make You Gain Weight?

One of the main concerns of people on a diet or those maintaining their weight is whether vitamin D3 causes weight gain. In this regard, the opposite happens: if you get little sun or eat few foods that contain it, you could experience weight gain.

The reason is that vitamin D, along with calcium, stimulates the use of fats to provide energy to the body. If these fats are not used, they are stored as adipose tissue, which forms the “love handles.”