USEFUL ARTICLES

USEFUL ARTICLES

14.11.2024

Vitamins

It is difficult to overestimate the usefulness and vital necessity of vitamins. The functioning of the human body is impossible without vitamins. And the proper functioning of the body directly depends on a constant and optimal balance of all vitamins. And sometimes, when this balance is disturbed, both by the fault of consumers themselves, and on the recommendations of "near-medical" consultants, intrusive advertising, a person is exposed to danger and serious risks, the consequences of which may manifest themselves years later, and the reasons for this, and will not be timely identified and corrected.

Let's try to figure out
Vitamin A
The term "vitamin A" includes two groups of fat-soluble biologically active substances: retinoids, which are found in animal products and have direct vitamin activity, and carotenoids (provitamins), which are found in plant products and are converted into vitamin A as needed. Our review focuses on the effects of natural retinoids. In animal products, retinol is usually present in the form of retinol palmitate ester.
- Vitamin A is a fat-soluble vitamin whose most important and proven benefit is its participation in the synthesis of rhodopsin. This is the visual pigment of the eye that is responsible for adapting vision to darkness and distinguishing colors. Normal levels of vitamin A in the body reduce the risk of retinal problems and age-related vision loss.
BUT! If the diet includes foods or supplements with even an average level of vitamin A and regular exposure to the open sun without eye protection (sunglasses with UV filters), the likelihood and severity of damage to the tissues and structures of the eye due to oxidation of retinol by ultraviolet light increases significantly. In this case, retinol serves as a photosensitive acceptor of solar photons, and after the retinol molecule is modified and oxidized, it has a destructive and threatening effect on the tissues of the eye.
- One of the most important properties of vitamin A is that it is a component of most membranes. It stimulates the production of collagen, which affects the elasticity of the skin. Vitamin A affects the renewal of epidermal cells - the surface layer of the skin, which is constantly sloughing off and renewing itself. It also normalizes the production of sebum.
BUT! with the accumulation of vitamin A in the skin, and subsequently in excess, it causes dry skin, and, as mentioned above, at the same time, in contact with unprotected skin with ultraviolet light, initiates a deeper sunburn, and, significantly increases the probability of damage to skin cells, mutagenesis and carcinogenesis of basal cells of the pidermis. The "duplicity" of vitamin A is that in certain concentrations, without contact with solar ultraviolet, vitamin A shows itself in some tissues, albeit weakly, but as an anticarcinogenic substance, inhibiting proliferation, regulating cell differentiation, but, in contact with UV photons, acquires carcinogenic property, destructive and mutagenically affecting neighboring tissues. More complexly, under the influence of UV light, vitamin A molecules are transformed into free radicals, causing oxidative stress, negatively affecting the genome of the cell, acquiring mutagenic and oncogenic potential. The possible initiation of lung cancer by excessive vitamin A intake and accumulation follows much the same pathophysiologic vector described above. Only instead of ultraviolet light, tobacco smoke acts as an oxidant and modifier of vitamin A in the lungs.
- Yes, vitamin A is very important for the immune system, it is involved in the synthesis of leukocytes - protective blood cells, antibodies. That is, vitamin A is involved in the fight against infections. And another of the functions of vitamin A - its effect on reproductive function in women, fetal protection and embryo development. All fat-soluble vitamins are very necessary for the reproductive system because hormones are involved in fat metabolism and the accompanying vitamins are very important cofactors. For example, men need vitamin A for sperm production. And women need vitamin A during pregnancy because new growing cells are constantly needed for the development of the fetus. This is why vitamin A is essential in multivitamins for pregnant women.
BUT! Uncontrolled and prolonged use of vitamin A can lead to completely opposite effects: reduced production of testosterone and reduced spermatogenesis, brittle bones, reduced function of T and B lymphocytes and, instead of benefits for the fetus, to teratogenic effect in its intrauterine development and, accordingly - to abnormalities of fetal development.

Vitamin K
This vitamin regulates blood clotting, maintains bone strength and blood vessel health.
Deficiency of this vitamin is rare because its level is maintained both by diet and synthesis by the intestinal microbiota, but for example, long-term antibiotics and/or lack of vegetables and fiber in the diet can lead to a deficiency of this vitamin and subsequently to bleeding and other pathologies. BUT! People over 50 who consume a lot of such products (e.g. daily smoothies of greens) as: dill, celery, green onions and especially parsley (more than 5 daily norms of vitamin per 100 grams of product), in summer, hot time accompanied by regular dehydration (dehydration, thirst), can carry a risk of thrombosis (heart attack, stroke, occlusion of the lower extremities), especially in people with diabetes and the elderly!

What new research shows

Vitamin B1
Biologists have discovered how vitamin B1 interacts with cancer cells.
The resistance of tumor cells to drugs depends on it.
Scientists have discovered how vitamin B1 affects cancer cells. It turns out that in some cases it increases their resistance to chemotherapy, and in other cases it decreases it. This should be taken into account when choosing a therapy. The results of the study were published in the journal Frontiers in Genetics.
It turns out that the effectiveness of anti-tumor therapy may depend on a combination of the adaptation of cancer cells to anti-tumor drugs and the availability of thiamine, vitamin B1, to the cells.
In recent years, biologists and medical scientists have begun to actively study the role that different forms of vitamin B play in the development of cancerous tumors and in how actively the body tries to fight them. Experiments show that many types of cancer cells actively take up molecules of these substances, making it possible to fight tumors by depriving them of access to vitamin B or by coating them with nanoparticle molecules that can destroy cancer.
At the same time, the bodies of many cancer patients are severely deficient in vitamin B, which in itself is dangerous for their bodies. In recent years, doctors and scientists have been actively discussing the possibility of using vitamin B to improve the health of patients. However, the safety of doing so is still not completely clear: scientists do not yet fully understand the role it plays in the vital processes inside cancer cells.
In the new work, scientists from Sweden tracked how large amounts of vitamin B1 affected the viability of several cultures of lung cancer cells, as well as how well they resisted the action of one of the popular anticancer drugs - cisplatin. Some of the cell cultures were very susceptible to chemotherapy, while others were resistant to cisplatin due to mutations in the p21 gene (on which this drug works).
These same mistakes in the DNA, according to Swedish biologists, had an unusual effect on how vitamin B1 affected the behavior of cancer cells. When the p21 gene was damaged, thiamine increased the effect of cisplatin and deprived cancer cells of resistance to the action of chemotherapy, and in the absence of such mutations observed the opposite picture - cancer cells stopped responding to the drug.
Such results, according to scientists, suggest that the concentration of vitamin B1 in the body of cancer patients should be taken into account when selecting drugs and strategies to combat the tumor. This is especially true for those patients whose malignancies are almost untreatable.

Vitamin B3
and the Risk of Cardiovascular Complications
The journal Nature Medicine published an article on vitamin B3, which is found in most multivitamin complexes.
In a study of more than 4500 people, it was shown that an excess of vitamin B3 metabolites correlates with an increased risk of heart attacks, including fatal ones.
This study looked at metabolites of vitamin B3, specifically one of its forms, niacin (nicotinic acid). With an excess of vitamin B3 in the blood plasma of the subjects studied, increased concentrations of two metabolites - 2PY and 4PY - were observed. This, in turn, correlated with an increased risk of serious cardiovascular complications. Elevated 2PY levels were associated with a 64% increased risk of myocardial infarction during the three-year follow-up period (US) and a 102% increased risk among Europeans. For individuals, the risks were even higher in the presence of the rs10496731 polymorphism.
Thus, uncontrolled vitamin intake can have serious negative consequences.

For B6 and B12, scientists have found a link between vitamin intake and an increased risk of lung cancer.
Vitamin supplements are used to treat a variety of health problems when the body is deficient in vitamins and minerals from the diet. B vitamins have been shown to help with a number of conditions, including fatigue, vision problems, nervous system dysfunction, and even depression. But the shocking fact is that these vitamins can actually lead to an increased risk of lung cancer, especially in men. So what is the link?
With around 46% of adults in the UK reporting that they take extra vitamins B6 and B12 as part of their regular multivitamin tablets, there may be concerns about the link between these vitamins and an increased risk of lung cancer.
According to the study, men, especially men who smoke, have a higher risk of lung cancer if they take extra high doses of vitamins B6 and B12.
Men who took these vitamin supplements had almost double the risk of lung cancer. And the risk of lung cancer was three to four times higher in men who smoked, the study found.
"To avoid lung cancer, especially in men, you should not supplement with high doses of vitamins B6 and B12, and male smokers may be harmed by these vitamins," said Theodore Brasky, the study's lead author, a researcher and assistant professor at Ohio State University. For the study, researchers surveyed more than 77,000 people, asking them how often they took these B vitamins. The study also took into account factors such as the dosage of vitamins taken and usual dietary intake over the previous 10 years.
After six years, the researchers checked the health of the study participants to look for signs of lung cancer. And, after testing many indicators known to affect cancer risk, the researchers reported a 30 percent increased risk of lung cancer associated with vitamin B12 (taken as a stand-alone vitamin) and a 40 percent increased risk in those who took vitamin B6.
Strikingly, men who took one or the other vitamin in high doses for 10 years nearly doubled their risk of developing lung cancer, and the increase was even greater in male smokers. "Men who took more than 55 micrograms of vitamin B12 per day had a 98% higher risk of lung cancer than men who took no B vitamins," Brasky added."Men who smoked and consumed large amounts of B vitamins at the beginning of the study were three to four times more likely to get lung cancer," he said."Vitamin B6 is usually sold in 100-mg (milligram) tablets. And vitamin B12 is often sold in tablets of 500 mcg (micrograms) to 3,000 mcg.
In contrast, most multivitamins contain 100% of the U.S. RDA, which is less than 2 milligrams per day for vitamin B6 and 2.4 micrograms per day for vitamin B12.
In fact, people should ask themselves if they need such an amount of a substance that is tens or hundreds of times the RDA.
According to the National Library of Health, the potential role of B vitamins in cancer risk has been written about before."The results of two large randomized controlled trials conducted in Norway and associated with B vitamin supplementation suggest an increased risk of malignancy in individuals who received both vitamin B12 and B9 (folic acid), a finding based primarily on lung cancer data," he added. And according to a recent cohort study conducted by the Vitamins and Lifestyle/VITAL program, "men who consumed high amounts of vitamins B12 and B6 had a higher risk of lung cancer. Combined with the vitamin A discussed at the beginning of this article, getting more than the recommended amount of vitamin A in your diet will increase the likelihood of lung cancer even more.

Vitamin C, E
A new study has found that antioxidants may stimulate the growth of blood vessels in cancerous tumors. A new study has found that antioxidants such as vitamins C and E activate a mechanism that stimulates the growth of new blood vessels in cancerous tumors. Researchers say their findings highlight the potential risks of taking antioxidant supplements when they are not needed.
To grow and metastasize, cancerous tumors need a constant flow of oxygen- and nutrient-rich blood. This requires the formation of new blood vessels from existing ones, a process known as angiogenesis. When tissues are deprived of oxygen (hypoxia), cancer cells in the affected area send chemical signals that stimulate the endothelial cells lining the blood vessels to form new blood vessels.
A new study from Sweden's Karolinska Institute has investigated the mechanisms of angiogenesis and found that antioxidants play an unexpected role in tumor growth and spread.
Normally, antioxidants remove free oxygen radicals from the body's cells and reduce damage caused by oxidative stress. Oxidative stress is known to damage DNA and regulate the development of several cancers, including breast, lung, liver, colon, prostate, ovarian and brain cancers.
"You don't need to be afraid of antioxidants found in regular foods, but most people don't need to take special supplements. In fact, it may be harmful for cancer patients and people at increased risk of developing cancer," the researchers wrote.
Previously, researchers found that antioxidants such as vitamins C and E accelerate the growth and spread of lung cancer by stabilizing the BACH1 protein. The protein is activated when levels of free radicals in the body drop. This can happen when supplemental antioxidants are added to the diet or when spontaneous mutations occur in tumors that activate antioxidant production.
The researchers found that BACH1 can also induce angiogenesis by a mechanism that does not require hypoxia. This means that tumors can form new blood vessels at normal oxygen levels. They also found that BACH1 is regulated in a manner similar to the hypoxia-inducible factor 1-alpha (HIF-1-alpha) protein, the expression of which has been implicated in angiogenesis-driven tumor growth and metastasis. Therefore, the researchers hypothesized that these two proteins work together.
Another study, conducted for more than 20 by the staff of the Medical School of the University of Concepcion, showed that about 20 types of cancer cells actively absorb vitamin C, which is, in fact, their nutritional subject.
"Vitamin C, so essential for the normal functioning of the human body, performs many functions, mainly being a powerful antioxidant and a kind of builder of human tissues," commented the results of the work of the project leader, Professor Coralia Rivas of the School of Medicine. - We do not want our research to lead to a negative attitude towards this important vitamin, but the fact that it actively feeds cancer cells leaves no doubt.
In addition to these positive functions of vitamin C, the researchers point out its demand for energy to fuel healthy cells, the production of collagen - a protein that is the basis of all human organs and tissues, as well as active participation in the formation and transmission of nerve impulses. Vitamin C is also involved in the production and maintenance of human immunity.
The truth in the middle
The authors of the study explain that two types of vitamin C coexist in the body: its oxidized form - dishydroascorbic acid (DHA) - and its "reduced" form - direct ascorbic acid (AA).
AA has been shown to have a pronounced antioxidant effect on human cells and is not characterized by any selectivity towards cancer cells.
DGA is "treacherous" to malignant cells because cancer cells actively absorb this acid, attract it and surround themselves with it. Thus, DHA becomes a kind of nutrient reservoir for pathologically altered cells, the report notes.
"Characteristically, cancer cells in breast, prostate and blood cancers are able to accumulate vitamin C to a significantly greater extent than healthy cells," says Rivas.
"For scientists, our discovery is still very important and because we were able to show that vitamin C increases the vitality of already poorly curable types of tumors, minimizing the effect of chemotherapy and X-ray therapy", - explains the scientist.
In this case, cancer cells absorb a large amount of antioxidants, and in this case, vitamin C acts as their ally.
The next stage is the search for new methods of treatment
To deprive tumor cells of vitamin C, Chilean scientists are beginning to develop ways "at the level of the mitochondria (the structure that provides energy to cells in the body) to block the transport of the vitamin into the cancer cell," says Rivas.
Scientists at Karolinska University in Sweden conducted a study and found that some vitamins, when overdosed, can provoke the development of cancer. The study was published in The Journal of Clinical Investigation.
According to researchers, such risks are characteristic of vitamins E and C. Specialists have found that exceeding the concentration of these vitamins stimulates the growth of new blood vessels, resulting in tissue oxygen saturation. In addition, vitamins C and E are antioxidants and inhibit oxidative processes in tissues.
These conditions, according to scientists, are favorable for the development of cancer cells. Conducting research on rodents, experts found that with an overabundance of vitamins C and E consumption in the body there is a growth of blood vessels, including in malignant tumors.
The question of the benefits or harms of tocopherol is not an idle one. Many people believe that taking vitamins and supplements will protect them from many diseases, including cancer.
But studies show that dietary supplements do not provide any protection and can sometimes be harmful and increase the risk of cancer. Recently, scientists from the city of Boston in Massachusetts (USA) decided to understand how vitamin E intake affects the likelihood of cancer in general and some types of cancer in particular, and what factors might influence its effects.
Kathryn Hall, one of the study's co-authors, notes:
Observational studies in humans have shown benefits [of vitamin E supplementation], and protective effects have been demonstrated in animal studies, but when vitamin E supplements were studied in placebo-controlled trials, the results were null. This suggested that vitamin E didn't really work. But we found that it may have a protective effect in some people, and that it was due to certain genetic traits.
To understand the benefits and harms of tocopherol, researchers analyzed some data:
Results from the Women's Health Study (WHS), which looked at the benefits and risks of low-dose vitamin E and aspirin in preventing cardiovascular disease and cancer in thousands of women in the United States. The Women's Genome Health Study helped provide information about the genes of the WHS participants.
Results from a study of cancer prevention with alpha-tocopherol and beta-carotene.
It turns out that the effect of vitamin E on cancer risk (both positive and negative) depends on the specifics of the COMT gene. This gene codes for the enzyme catechol-O-methyltransferase, which influences the metabolism of tocopherol in the human body.
Three alleles (variants) of the COMT gene are best known to scientists. They are called met/met, val/met, and val/val.
Carriers of the val/val allele were found to have 3-4 times higher catechol-O-methyltransferase activity than those with the met/met variant. Study participants who carried the met/met allele and took vitamin E had a 14% lower incidence of cancer than those who also carried the met/met variant and took a placebo.The situation was different for the val/val allele. In contrast, the incidence of cancer was 15% higher among women in this group who took tocopherol compared with the placebo group.This difference persisted when looking at individual types of cancer, such as breast, lung, uterus, colon and rectum. In the near future, scientists plan to understand the molecular mechanisms by which vitamins have such a different effect on cancer risk in different people.

Vitamin D3
Scientists: Vitamin D3 and omega-3 do not help slow aging
A large study has shown that taking supplements does not improve the condition of the elderly. Exercise and diet are more effective in preventing senile infirmity, scientists say. They insist that society should promote healthy lifestyles instead of relying on the use of drugs.
The study by American scientists involved 25 thousand volunteers over 50 years old. They were divided into four groups: the first group was assigned to take vitamin D3 (2000 ME per day) and omega-3 (840 mcg per day), the second and third - one of these supplements, and participants from the last group were the control group. Before the experiment, which lasted five years, 3,174 people were identified in the "frail" group who already showed signs of senile infirmity.
Based on their observations, the researchers concluded that there was no significant difference between the participants. Five years later, another 2,487 people from different groups moved into the frail category.
Vitamin D did not reduce fracture risk in adults
A five-year randomized trial involving nearly 26,000 people found that taking 2,000 international units of vitamin D3 daily did not reduce the risk of fractures in healthy American adults compared with taking a placebo. According to an article published in the New England Journal of Medicine (LeBoff et al, Supplemental Vitamin D and Incident Fractures in Midlife and Older Adults), the difference in risk between the groups remained statistically insignificant after adjusting for age, sex, race, body mass index, and serum 25-hydroxyvitamin D concentration.Of the many effects of vitamin D, physicians are more often interested in its effects on the skeletal system because it maintains adequate blood calcium levels, which are necessary for bone mineralization. In addition, vitamin D receptors have been found in the bones themselves, and their activation has been linked to the development of osteoblasts and bone formation. Decreased mineralization of bone tissue leads to osteoporosis - disruption of the architecture of bone tissue and reduction in its density, ultimately leading to bone fragility and pathological fractures in adulthood.
Because such fractures are a major public health problem (for example, two million osteoporotic fractures are reported annually in the United States), prevention is a concern for physicians worldwide. In 2011, the U.S. National Academy of Medicine set the recommended preventive dose of vitamin D for adults at 600 to 800 international units per day, which meets the body's needs for bone health in 97.5 percent of the population.
Meryl LeBoff and colleagues at Harvard Medical School used data from the VITAL trial, which examined the effect of taking 2,000 international units of vitamin D and/or one gram of omega-3 unsaturated fatty acids on the risk of cardiovascular disease and cancer in American adults. A total of 25871 healthy individuals (men over 50 years of age, women over 55 years of age) were enrolled in the new study and evenly divided into those who took two thousand international units of vitamin D daily and those who took a placebo. The mean age of the participants was 67.1±7.1 years. There were equal numbers of men and women, and 20.2 percent of the participants were black.
Baseline characteristics (age, sex, race, body mass index, and supplemental calcium or vitamin D intake) did not significantly affect the results of the study. Participants' baseline serum 25-hydroxyvitamin D levels also did not alter the likelihood of all three types of fracture.
Serum calcium levels (measured in 15884 participants) and parathyroid hormone levels (measured in 16803 participants) also did not affect fracture incidence. The researchers found no significant differences in fracture incidence among participants taking osteoporosis medications. In terms of side effects, there were no significant differences in the incidence of increased blood calcium and kidney stone formation between the groups.
This study shows that taking an additional 2,000 international units of vitamin D3 daily does not reduce the risk of fracture in healthy adult men and women compared with placebo. The difference between the groups remained small even after adjusting for age, sex, race, serum 25-hydroxyvitamin D concentration, and other parameters.
Yes, in the human body, the determining basis of physiological processes are genes. The "conductor's baton" could be called hormones. But hormones initiate enzymatic reactions, the key to which happens to be vitamins. This means that they play a key role. And this fact requires a very serious, careful and attentive attitude to them and to nutrition, and a proper interaction with the micro and macro environment.


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