Can vitamin D fight cancer?
2023-11-16
As early as 1824, someone discovered that cod liver oil could treat rickets. In 1918, Lord Mellanby of the United Kingdom confirmed that rickets was a nutritional deficiency, but he mistakenly believed that it was caused by a lack of vitamin A. Later, Adolf Windaus of the University of Göttingen in Germany first determined the chemical structure of vitamin D. He won the 1928 Nobel Prize in Chemistry for his study of the composition of cholesterol and its relationship with vitamins, and his discovery of vitamin D.
Vitamin D and pancreatic cancer
In 1921, McCollum named vitamin D. Judging from the name, it was the fourth vitamin discovered by humans. However, people at the time did not know that this thing was different from other vitamins because as long as there are ultraviolet rays, people themselves Can synthesize vitamin D.
Vitamin D is a sterol derivative that has an anti-rickets effect and is also called an anti-rickets vitamin. The most important members of the vitamin D family are vitamin D2 (ergocalciferol) and vitamin D3 (cholecalciferol). In 1932, the chemical properties of vitamin D2, obtained by irradiating ergosterol with ultraviolet light, were elucidated. The chemical properties of vitamin D3 were determined in 1936.
The vitamin D family are all derivatives of different provitamins that have been exposed to ultraviolet rays. Plants do not contain vitamin D, but provitamin D exists in both animals and plants. Vitamin D is a fat-soluble vitamin with five compounds. Vitamin D2 and vitamin D3 are more closely related to health, and they are found in some natural foods. The human body stores 7-dehydrocholesterol generated from cholesterol under the skin. After being exposed to ultraviolet rays, it can be converted into vitamin D3. Proper sunbathing is enough to meet the body's need for vitamin D.
These are just what people have known about vitamin D in the past. Today, however, it is discovered that vitamin D has a wide range of effects and is even related to the treatment of cancer. From the pancreatic cancer cases of several celebrities, we can know how important vitamin D is.
IT elite Steve Jobs, the developer of Apple Computer, and Steinman, one of the winners of the 2011 Nobel Prize in Physiology or Medicine, both died prematurely of pancreatic cancer. The former only lived to be 56 years old, and the latter was 68 years old. In addition to the huge misfortune of suffering from cancer, Jobs and Steinman also had even more embarrassing regrets.
Steinman was diagnosed with pancreatic cancer in 2007. After treatment, he survived for 4 years. The most regrettable thing is that Steinman passed away on September 30, three days before the Nobel Prize Review Committee announced that he had won the 2011 Nobel Prize in Physiology or Medicine, and was unable to hear the news of his award in person. Goran Hansson, chairman of the Nobel Prize in Physiology or Medicine jury, said we "regret that he cannot feel this joy."
Jobs was diagnosed with pancreatic cancer in 2003. After treatment and battle, he still survived for 8 years. Jobs died on October 5, five days after Steinman's death. He also left his biggest regret - that he was unable to recognize and reconcile with his biological father during his lifetime, even though his biological father wanted to take the initiative to give him a medical checkup after knowing that Jobs was ill. However, he was worried that people would misunderstand that it was for Jobs' money (Jobs left a fortune of US$8.3 billion after his death), so he never did so.
Researchers now believe that due to lack of vitamin D, some effective drugs to treat pancreatic cancer cannot work, thus leaving countless people like Jobs and Steinman suffering from pancreatic cancer without effective treatment and dying young. If vitamin D can be added to chemotherapy, many patients can not only prolong their survival, but also potentially be cured.
The anti-cancer mechanism of vitamin D
Pancreatic cancer is a cancer among cancers, and its biggest characteristic is its extremely high mortality rate. After patients develop pancreatic cancer symptoms (upper abdominal discomfort, dull pain, jaundice, etc.) and are diagnosed, the average life expectancy is only about 9 months, and the 5-year survival rate is less than 2%. 90% of pancreatic cancer originates from ductal adenocarcinoma of the glandular epithelium. Moreover, the early diagnosis rate of pancreatic cancer is not high, the surgical mortality rate is also high, and the cure rate is very low.
Now, Ronald Evans and others from the Sulk Institute in the United States have published a paper in the journal Cell stating that a vitamin D derivative (vitamin D-like drug) can disintegrate the cell barrier that protects pancreatic tumors, making this An indestructible cancer is more sensitive to drugs. This vitamin D derivative can prevent the fibrosis process and may also play an important role in promoting the curative effect of other cancers, such as lung cancer, kidney cancer, liver cancer and other refractory tumors.
Pancreatic cancer, like other cancers, is difficult to treat because cancer cells can protect themselves through fibrosis. For example, pancreatic tumor cells can send out some signals to interact with adjacent cells, causing a local inflammatory reaction, which in turn produces fibrosis, forming a shield around the tumor cells, thereby blocking immune cells and drugs from entering the tumor cells and attacking them. to attack. This mechanism leads to tumor drug resistance, making it difficult to cure pancreatic cancer.
The researchers believe that if they can prevent the inflammatory response around tumor cells, they can avoid the formation of fibrosis, the shield that protects tumor cells. In the past, researchers could not find a suitable way to prevent cancer fibrosis. Now, researchers have found that vitamin D may be a better and simpler way to prevent cancer fibrosis.
In the past, it was known that pancreatic astrocytes were key to forming the tumor cell shield. When minor damage occurs to the tissue, astrocytes can quickly become activated, which has the effect of promoting cell proliferation. In cancer tissues, astrocytes are continuously activated. Activated astrocytes not only provide additional cell growth factors to tumor cells and promote tumor cell proliferation, but also help form a local barrier to protect tumor cells - fibrosis.
In 2013, Evans and others discovered that a vitamin D derivative had the effect of inactivating liver astrocytes, and they speculated that this effect may also exist in the pancreas. In the past, it was believed that pancreatic tissue did not have vitamin D receptors, and it was therefore inferred that vitamin D derivatives could not inactivate pancreatic astrocytes. In fact, 32 tissues or organs in the human body contain vitamin D receptors. When the researchers analyzed the difference between activation and inactivation of pancreatic astrocytes, they found that activated astrocytes surrounding tumor cells expressed high levels of vitamin D receptors. More importantly, when vitamin D derivatives were added to In activated astrocytes, these cells quickly return to a healthy, inactive state, stopping generating signals that stimulate growth and inflammation, thus stopping stimulating tumor growth and preventing inflammation, thereby blocking fibrous barrier formation.
So why doesn’t natural vitamin D inactivate activated astrocytes? The reason is that activated astrocytes can quickly break down ordinary vitamin D and prevent vitamin D from binding to receptors. However, activated astrocytes cannot break down vitamin D derivatives and cannot prevent vitamin D derivatives from binding to receptors.
Based on this research, Evans believes that the key is that vitamin D may be able to maintain normal astrocyte vitamin D receptor signaling before tumor cells activate astrocytes, thereby inhibiting cancer growth. Previously, researchers have clinically tested the use of vitamin D combined with chemotherapy drugs to treat pancreatic cancer, but activated astrocytes can decompose vitamin D and therefore failed to produce therapeutic effects.
Now, if vitamin D and chemotherapy drugs can be used before tumor cells activate astrocytes, or vitamin D derivatives combined with chemotherapy drugs can be used to treat pancreatic cancer, it may be possible to effectively treat pancreatic cancer. Experiments by Evans and others showed that combining this vitamin D derivative with some chemotherapy drugs to treat pancreatic cancer mice can extend the lifespan of cancer-stricken mice by 50%.
However, Evans and others did not clarify whether this special form of vitamin D, that is, a vitamin D derivative or vitamin D-like compound, is vitamin D2 or D3, or a new vitamin D derivative. Several previous studies have shown that taking vitamin D can reduce the risk of pancreatic cancer. In 2006, Harvard University in the United States surveyed more than 46,000 men and women.
A follow-up survey of more than 75,000 women showed that 12.5 per 100,000 people who consumed more than 600 IU of vitamin D per day developed pancreatic cancer, while 12.5 per 100,000 people who consumed less than 150 IU of vitamin D per day developed pancreatic cancer. 21 people developed pancreatic cancer.
The research by Evans and others has certainly opened up broader prospects for the use of vitamin D. However, it will take more time and more research to hope that vitamin D will have a specific effect on cancer, especially pancreatic cancer. confirmed. The reason is that firstly, which derivative of vitamin D is effective in preventing cancer fibrosis needs to be determined, and secondly, this vitamin D derivative needs to be clinically tested in combination with other cancer chemotherapy drugs to confirm the effect.
Various new functions of vitamin D
In addition to participating in the prevention and treatment of cancer, vitamin D also plays a role in the prevention and treatment of various diseases and in promoting human health, but people have not realized it before. In the past, vitamin D deficiency was linked to diabetes, but now new research is linking it to infections and mental illness.
1. Vitamin D helps babies fight respiratory infections.
A study conducted on pregnant women by Grant and others from the University of Oakland in the United States found that after pregnant women supplemented with vitamin D, the probability of infants developing respiratory tract infections was reduced. The study was divided into a vitamin D group and a placebo group. Mothers in the vitamin D group were given daily vitamin D during the second half of pregnancy. It was found that babies born to these women were less likely to develop any respiratory infections until they were 6 months old, and this effect continued for up to 18 months. But babies born to women in the placebo group often developed respiratory infections.
When women take vitamin D during pregnancy, they refer to taking a daily dose of vitamin D, rather than supplementing with a large dose of vitamin D. This dose is 200 international units per day, which is equivalent to 5 micrograms, and should not be more. As long as pregnant women supplement this dose daily, they can maintain sufficient levels of vitamin D in their newborn babies and reduce their respiratory tract infections.
2. Vitamin D is associated with a variety of mental illnesses.
Recent research by Asmailzadeh's research team at the School of Medicine at the University of Isfahan in Iran found that vitamin D deficiency may induce schizophrenia in people. Individuals with vitamin D deficiency are twice as likely to develop schizophrenia as normal individuals (people with sufficient vitamin D levels).
Schizophrenia mainly manifests as delusions and hallucinations. Since the disease is more prevalent in cold climates and high latitudes, researchers have always speculated that vitamin D and schizophrenia are inextricably linked. To this end, Asmailzad's research team tested the vitamin D levels of 2,804 adult volunteers and assessed their mental health.
The results found that patients with schizophrenia had significantly lower levels of vitamin D. Specifically, patients with schizophrenia had an average of 5.91 nanograms per milliliter of blood less than normal people. The risk of developing schizophrenia for people with vitamin D deficiency is 2.16 times higher than that of normal people. At the same time, 65% of schizophrenia patients will suffer from vitamin D deficiency.
The study by Esmailzadeh and others is the first to clearly point out that vitamin D deficiency is related to schizophrenia. In addition, other studies have linked vitamin D deficiency to other mental illnesses, such as Alzheimer's disease.
Llewellyn and others from the University of Exeter Medical School in the UK conducted a study on 1,658 elderly people aged 65 and over. At the start of the study, they were all able to walk independently and were free of Alzheimer's disease, cardiovascular disease and stroke. They were then followed for six years to see who developed Alzheimer's and other forms of dementia.
It was found that people with minor vitamin D deficiencies had a 53% increased risk of developing Alzheimer's disease and any form of dementia, and those with severe vitamin D deficiencies had a 53% increased risk of developing Alzheimer's disease and any form of dementia. The risk increases by 125%.
Therefore, the role of vitamin D on human health should be given sufficient attention today.
