Vitamin D

Vitamin D3 for immunity

Do you feel like you catch every possible infection every fall and winter? Do you feel that your child brings home new viruses from kindergarten, and you are out of commission for a week with them? This may be a sign that your immune system doesn't have the fuel to work, and that fuel is precisely vitamin D.

Vitamin D acts like a key in the ignition for your immune cells, especially T lymphocytes. They are the elite special forces of your body, which can recognize and destroy cells infected with viruses and bacteria. Without an adequate level of vitamin D, these cells remain dormant – they are present, but inactive. They cannot effectively react to a threat. When you supply your body with vitamin D, you give them the signal to "wake up" and get ready to fight.

What does this mean in practice? Your body copes with infections much more efficiently. Scientific studies unequivocally confirm that people with a proper level of vitamin D get the flu and colds less often, and if they do get sick, the infection lasts shorter and has a milder course. Vitamin D supplementation is like year-round training for your immune army. You ensure its combat readiness, so you can enjoy health and carry out your plans without worrying about a sudden illness.

Strong bones and healthy teeth for life: Get to know the perfect duo of vitamins D3 and K2

Vitamin D3 – the conductor of calcium in your body

The main task of vitamin D in the context of bones is to increase the absorption of calcium and phosphorus from the intestines. This is absolutely crucial, because without it, even a calcium-rich diet would be of little use. Vitamin D acts like a conductor who ensures that valuable minerals from food get into the bloodstream and are available to the body. However, its role ends there. Vitamin D introduces calcium "to the party," but does not tell it where to sit.

Vitamin K2 (MK-7) – a navigator that directs calcium straight to its destination

And this is where vitamin K2 comes in, specifically its most active form, MK-7. It acts as a precise navigator. It activates a special protein called osteocalcin, which is responsible for binding calcium and building it into the structure of bones and teeth. Thanks to this, calcium goes exactly where it is needed, strengthening bones and protecting against osteoporosis.

What's more, vitamin K2 activates another protein (MGP) that prevents calcium from depositing in arteries and soft tissues. This is an extremely important benefit! It means that the D3+K2 duo not only takes care of strong bones but also supports the health of the circulatory system, protecting blood vessels from calcification, which leads to their stiffness and the development of atherosclerosis. By choosing a supplement that combines vitamin D3 with K2, you give yourself a double benefit – you invest in healthy bones and flexible arteries for many years to come.

The effect of vitamin D3 on well-being

Do you feel that with the arrival of autumn and winter, your mood drops? Do you lack energy, motivation, and the world seems grayer? This phenomenon, known as seasonal depression or "winter blues," is strongly related to the lack of sunlight and... vitamin D.

Your brain is an organ extremely rich in vitamin D receptors. They are located in areas responsible for regulating mood, emotions, and cognitive functions. Vitamin D plays a key role in the production of serotonin – a neurotransmitter commonly called the "happiness hormone." An adequate level of serotonin provides a feeling of calmness, satisfaction, and emotional stability.

When the level of vitamin D in the body drops, the production of serotonin can also be disturbed. The effect is a lowered mood, irritability, a feeling of apathy, and problems with concentration. Regular vitamin D supplementation, especially during the period from September to April, is a natural and effective way to maintain chemical balance in the brain. It's like giving yourself a dose of sunshine on a cloudy day, which helps disperse the clouds not only in the sky but also in your head.

Capsules or drops? Which vitamin D3 to choose?

• Vitamin D in capsules: This is the most popular and very convenient form. Capsules, most often gel-based with oil, ensure good absorption, because vitamin D is fat-soluble. They are easy to store and ideal for people who value simplicity – one capsule and the matter is settled.
• Vitamin D in drops: This is a fantastic option for the whole family. It allows for extremely precise dosing – you can easily adjust the number of drops to the needs of a child, an adult, or a senior. It is also an ideal solution for people who have trouble swallowing tablets. The drops can be administered directly into the mouth or added to a drink or meal.

What dose of vitamin D to use? Understanding IU units

Doses of vitamin D are given in international units (IU – International Units). The official Polish recommendations for healthy adults are supplementation in a dose of 1000-2000 IU in the period from September to April. However, many people, especially those who are overweight, seniors, or people who avoid the sun, may need higher doses.

• Doses of 2000-4000 IU: Considered optimal and safe for most adults to maintain a proper concentration of vitamin D in the blood.
• Doses of 5,000 IU, 10,000 IU, and higher: These are therapeutic doses, used to quickly supplement large deficiencies. Before you decide on such a high dose, the best and safest step is to have a blood test – to determine the concentration of the metabolite 25-(OH)D. The result of the test will allow you to precisely select the ideal dose for you.

Do I need to supplement with vitamin D in the summer?

In Poland, skin synthesis of vitamin D is effective from May to September, but under certain conditions: you must spend at least 15-20 minutes in the sun between 10:00 a.m. and 3:00 p.m., with your forearms and legs uncovered, and without using sunscreen. Many people, especially those who work in offices or regularly use UV-filter creams, may have deficiencies even in the summer. In this case, supplementation is recommended all year round.

Does vitamin D have to be taken with fat?

Yes, vitamin D is fat-soluble, which means that its absorption is much better in the presence of fat. Good quality supplements in capsules already contain oil (e.g., flaxseed, sunflower, MCT), which solves the problem. If you use drops or tablets without fat, it is best to take them with a meal containing fat, e.g., with avocado, nuts, olive oil, or eggs.

Is it possible to overdose on vitamin D?

An overdose of vitamin D is possible, but very rare and usually results from long-term use of extremely high doses (above 50,000 IU per day) without medical supervision. Symptoms of toxicity include nausea, weakness, and hypercalcemia (too high a level of calcium in the blood). The use of doses in the range of 4000-10,000 IU per day is considered safe for most adults, but at doses above 4000 IU, periodic blood level testing is recommended.

What are the symptoms of vitamin D3 deficiency?

Vitamin D3 is called the "sunshine vitamin" because the body produces it under the influence of UVB radiation. It is involved in regulating calcium-phosphate metabolism, supports immunity, and the proper functioning of muscles. Its deficiency is very common in Poland, especially during the autumn-winter period. Symptoms can be non-specific, which is why they are often disregarded. The most common are:

• Chronic fatigue and drowsiness – lack of energy despite a sufficient amount of sleep.
• Lowered mood, depressive states – vitamin D3 deficiency affects serotonin production.
• Weakened immunity – frequent infections, colds, and sinus problems.
• Bone and muscle pain – vitamin D3 is responsible for calcium metabolism and bone mineralization.
• Sleep problems – difficulty falling asleep or shallow sleep.
• In children – risk of rickets, slowed development of the skeletal system.
• In adults – osteoporosis, increased risk of fractures, joint pain.
• Hair loss and worsening skin condition.

What should not be combined with vitamin D3?

Vitamin D3 is fat-soluble, so it is best to take it with a meal containing healthy fats (e.g., avocado, olive oil, nuts). However, there are substances and medications that can weaken its action or increase the risk of adverse effects:

• Vitamin K in large doses – although D3 is often combined with K2 for bone health, this combination is contraindicated when taking anticoagulants (e.g., warfarin).
• Large doses of calcium – an excess of calcium with high D3 supplementation can lead to hypercalcemia (too high a level of calcium in the blood).
• Antiepileptic drugs (e.g., phenytoin, carbamazepine) – can weaken the action of vitamin D3.
• Corticosteroids (e.g., prednisone) – reduce calcium absorption and affect the metabolism of vitamin D.
• Some cholesterol-lowering drugs (cholestyramine, orlistat) – reduce fat absorption, and thus vitamin D3.
• Excessive alcohol – weakens the metabolism of vitamin D in the liver.

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