NEW YORK – Excessive intake of Vitamin A can have a negative effect on the human body, a new study says.
The research shows that Vitamin A plays a crucial role in energy production within cells but too much or too little of it can harm the system.
This is particularly important as combinations of foods, drinks, creams, and nutritional supplements containing added Vitamin A make an overdose more possible than ever before.
“Our work illuminates the value and potential harm of Vitamin A use in cosmetic creams and nutritional supplements,” said study co-author UlrichHammerling of Sloan-Kettering Institute for Cancer Research, New York.
“Although Vitamin A deficiency is not very common in our society, over-use of this vitamin could cause significant disregulation of energy production impacting cell growth and cell death.”
Though Vitamin A for nutrition and foetal development is well-known, it has been unclear why Vitamin A deficiencies and overdoses cause such widespread and profound harm to our organs, until now.
The discovery by Hammerling and colleagues explains why these effects occur, while also providing insight into Vitamin A’s anti-cancer effects, says a Sloan-Kettering release.
The scientists used cultures from both human and mice cells containing specific genetic modifications of the chemical pathways involved in mitochondrial (which powers the cell) energy production.
These findings were published in the FASEB Journal.
URMC Study Links Vitamin D, Race, And Cardiac Deaths
ROCHESTER – Vitamin D deficiency may contribute to a higher number of heart and stroke-related deaths among black Americans compared to whites, according to a University of Rochester Medical Center study.
The journal Annals of Family Medicine is publishing the study in the January-February edition, which goes online Jan. 11, 2010.
Researchers sought to understand the well-documented disparity between blacks and whites in cardiovascular deaths. They turned to vitamin D because growing evidence links low serum levels of D to many serious illnesses including diabetes, hypertension, kidney and heart disease.
Lead author KevinFiscella, M.D., said a complex host of genetic and lifestyle factors among blacks may explain why this population group has lower vitamin D levels across the lifespan than other races.
People get vitamin D through their diets, sun exposure, and oral supplements. Genetic factors common to blacks sometimes preclude vitamin D absorption, such as a higher incidence of lactose intolerance, which can eliminate vitamin-D fortified milk from the diet, and darker skin pigment that significantly reduces vitamin D synthesis.
“Therefore, our study suggests that the next step would be to intervene to boost vitamin D levels safely, with supplements,” said Fiscella, a national expert on disparities in health care and a professor of Family Medicine and Community and Preventive Medicine at URMC.
With funding through the National Heart Lung and Blood Institute, Fiscella and colleagues studied a sample of more than 15,000 American adults. The data included measurements of blood levels of vitamin D and death rates due to cardiovascular disease. Researchers also looked at other factors that contribute to heart health, such as body mass index, smoking status and levels of C-reactive protein.
Overall, the analysis showed that, as expected, a vitamin D deficiency was associated with higher rates of death among all people in the sample. In fact, those adults with the worst deficiency had a 40 percent higher risk of death from cardiac illness. This suggests that vitamin D may be a modifiable, independent risk factor for heart disease, Fiscella said.
Most striking, however, was that when researchers adjusted the statistics to look at race, blacks had a 38 percent higher risk of death than whites. As vitamin D levels rose, however, the risk of death was reduced. The same was true when researchers analyzed the effect of poverty on cardiovascular death rates among blacks, which suggests that vitamin D deficiency and poverty each exert separate risk factors, the study said.
A review article published in September 2009 in The American Journal of Medicine, noted that Vitamin D deficiency is a worldwide health problem. In the U.S., inadequate Vitamin D has been reported in about 36 percent of otherwise healthy young adults and about 57 percent of general medicine hospitalized patients.
Vitamin D is metabolized in the liver and converted to 25 hydroxyvitamin D or 25(OH) D, the form used to determine a person’s status through a blood test. Deficiency is usually defined by levels of less than 20 nanograms per milliliter; 30 ng/ml is viewed as sufficient. The mean blood level in the study sample was 29.5 ng/ml.
Most of the body’s tissues and cells have vitamin D receptors, making it a potent regulator of cell activity and growth. A deficiency contributes to inflammation associated with heart disease, many cancers and poor bone health.
Fiscella cautions, however, that not all observational studies of vitamin deficiency are borne out by subsequent clinical trials. For example, previous observational studies of vitamin E and beta-carotene that were associated with poor heart health did not hold up in later clinical studies. The need to further assess the vitamin D connection to heart disease is convincing, however, particularly among blacks, he added.
Other at-risk people include the obese and the elderly, (particularly housebound or nursing home residents), because vitamin D levels decline with age. And although more sun exposure can boost levels of D, skin cancer is also an increasing risk to many people. Therefore, medical authorities usually recommend increased dietary intake and/or supplementation as the best way to correct a deficiency.
Other names: All-heal, Amantilla, Setwall, Setewale, Capon’s Tail, Valeriana officinalis
Valerian is a plant native to Europe and Asia. It grows to up to four feet high and has trumpet-shaped flowers. The roots are used medicinally. Although the fresh root is relatively odorless, the dried root has a strong odor that many find unpleasant.
Valerian is believed to have been used since at least the time of ancient Greece and Rome. It was used as a folk remedy for a variety of conditions such as sleeping problems, digestive complaints, nervousness, trembling, tension headaches and heart palpitations. Valerian’s popularity waned with the introduction of prescription sleep medication.
There is no consensus on what the active constituents of valerian are. It’s possible that valerian’s activity may result from a combination of compounds rather than any one. Valerian appears to increase the body’s available supply of the neurotransmitter gamma aminobutyric acid (GABA), possibly by increasing its production, decreasing its absorption or slowing its breakdown.
Valerian can be found in capsule, tea, tablet or liquid extract forms in most health food stores, some drugstores and online.
Why Do People Use Valerian?
The use of valerian is supported by some evidence from clinical studies. The problem with many of the studies, however, is they’ve generally been small, used different amounts of valerian for varying lengths of time, or had problems with the study design, making it impossible to form a conclusion about the effectiveness of valerian.
Valerian appears to be less effective than prescription sleep medication. One possible advantage of valerian, however, is that it may not have as much of a “hangover” effect on mental or physical functioning the following day. Also, people taking sleeping pills sometimes have a temporary worsening of insomnia when they are discontinued, an effect that hasn’t been reported with valerian.
Valerian is also used for anxiety, although there’s insufficient evidence that it’s effective.
Side Effects and Safety Concerns
Pregnant or nursing women and children should not use valerian.
People taking medications for insomnia or anxiety, such as benzodiazepines, should not combine these medications with valerian.
Side effects of valerian may include headache, dizziness, itchiness, upset stomach, drowsiness during the daytime, dry mouth and vivid.dreams.
Rarely, liver damage has been associated with the use of valerian. It’s not certain whether the cause of the liver damage was due to valerian itself or to contaminants in the product. Until we know more, people should use valerian only under the supervision of a qualified health care practitioner and those with liver disease should avoid it. Although liver damage doesn’t always produce noticeable symptoms, if excessive tiredness, intense itching, nausea, vomiting, diarrhea, pain or discomfort in the upper right side of the abdomen, or a yellowing of the whites of the eyes or skin occurs, see your doctor immediately.
Valerian may cause excessive sleepiness or daytime drowsiness if combined with other drugs that cause drowsiness, such as the benzodiazepines Ativan (lorazepam) or Valium (diazepam), some antidepressants, narcotics such as codeine, and barbituates such as phenobarbitol, or with over-the-counter sleep and cold products containing diphenhydramine and doxylamine.
It may also cause excessive sleepiness if taken with herbs thought to have a sedative effect, such as hops, catnip and kava.
Valerian is broken down in the liver. Theoretically, it could interfere with the effectiveness of medications that are broken down by the same liver enzymes, such as:
allergy medications like Allegra (fexofenadine)
cholesterol medication such as Mevacor (lovastatin)
antifungal drugs such as Sporanox (itraconazole) and Nizoral (ketoconazole)
cancer medications such as Camptosar (irinotecan), Etopophos, Vepesid (etoposide), Gleevec (STI571), Taxol (paclitaxel), Velbe (vinblastine) or Oncovin (vincristine)
WASHINGTON – In a large-scale clinical trial in US and Canada, researchers at Rush University Medical Center are trying to find out if an over-the-counter vitamin-like substance, in high doses, can slow the progression of Parkinson’s disease.
The substance being tested, called coenzyme Q10, is produced naturally in the body and is an important link in the chain of chemical reactions that produce energy in mitochondria, the “powerhouses” of cells.
The enzyme is also a potent antioxidant – a chemical that “mops up” potentially harmful chemicals generated during normal metabolism.
“At present, the very best therapies we have for Parkinson’s can only mask the symptoms – they do not alter the underlying disease. Finding a treatment that can slow the degenerative course of Parkinsons’s is the holy grail of Parkinson’s research,” said neurologist Dr.KatieKompoliti, a specialist in movement disorders.
Many past studies have shown that Parkinson’s patients have impaired mitochondrial function and low levels of coenzyme Q10.
Moreover, laboratory research has demonstrated that coenzyme Q10 can protect the area of the brain damaged in Parkinson’s.
The Phase III clinical trial, a large, randomized study with a control group, follows an earlier investigation that tested several doses of coenzyme Q10 in a small group of patients with early-stage Parkinson’s disease.
The highest dose, 1,200 mg, appeared promising-over the course of 16 months, patients taking this dose experienced significantly less decline than other patients in motor (movement) function and ability to carry out activities of daily living, such as feeding or dressing themselves.
In the present trial, 600 patients will be enrolled at 60 centers in the U.S. and Canada.
Two dosages of coenzyme Q10 are being tested,1,200 mg and 2,400 mg, delivered in maple nut-flavored chewable wafers that also contain vitamin E.
Participants in the study will be evaluated periodically over 16 months for symptoms of Parkinson’s disease, including tremor, stiffness of the limbs and trunk, impaired balance and coordination, and slowing of movements.
They will also be assessed for ability to perform daily activities, overall quality of life, and need to take medications to alleviate symptoms.