acids, including EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid). There are two types of fish liver oil supplements: regular and fermented. Fermented fish liver oil supplements are more expensive compared to regular fish liver oil supplements. The fermentation process enhances the contents and purity of vitamin A, vitamin D, and the omega-3 fatty acids. The vitamin A in fish liver oil is a natural retinyl palmitate, which is the same as synthetic retinyl palmitate.
• Melanoma. Vitamin A can prevent melanoma. Clinical studies have shown that taking a dose of 4,000 IU of vitamin A daily for six months reduced the risk of melanoma by 40%. The protective effect was more profound in women than in men.
• Wrinkles. Vitamin A reduces wrinkles, making older skin look younger. Topical vitamin A at a dose of 0.4% applied three times weekly was effective in reducing wrinkles within weeks.
Safety Issues
• Overdose. Long-term consumption of high doses of vitamin A may cause hypervitaminosis A. Symptoms include blurred vision, lack of appetite, dry skin, and muscle weakness. High doses of vitamin A can cause liver damage as well as osteoporosis.
• Pregnant women. During pregnancy, women should take no more than 25,000 IU of vitamin A supplement daily to avoid hypervitaminosis A, which can lead to birth defects in infants.
• Recommended daily dose. Vitamin A is lipid-soluble and, once absorbed, will be retained in the body for a long time. It is recommended that you take no more than 10,000 IU of vitamin A per day.
What Types of Drugs May Interact with Vitamin A?
• Alcohol can exacerbate liver damage caused by high doses of vitamin A. Drinking alcoholic beverages with beef liver slices as a side dish is prevalent in some Asian cultures, which can lead to vitamin A toxicity. Furthermore, cholesterol-lowering drugs that hinder lipid absorption may also diminish vitamin A absorption.
• Long-term consumption of high doses of vitamin A can decrease vitamin K absorption, leading to vitamin K deficiency. Vitamin A enhances the drug action of warfarin. People who take warfarin to treat and prevent blood clots together with high-dose vitamin A should consult with health-care professionals.
Thiamine was the first B vitamin discovered; therefore, it was named vitamin B1. Vitamin B1 deficiency leads to beriberi disease. In 2600 BCE, ancient Chinese writings recorded the prevalence of beriberi disease in China. Dutch physicians in the 19th century noted that chickens fed only polished rice developed paralysis. Certain important nutrients seemed to be missing from polished rice. In the early 20th century, Casimir Funk isolated a water-soluble antineuritic substance from bran, the hard outer layer of cereal grain, and demonstrated that it could treat beriberi disease. He named the antineuritic substance “vitamine.” Vita in Latin means “life,” so a “vitamine” is required for life and was originally thought to be an amine.
Vitamin B1 obtained from foods is stored mostly in bones and muscles and the brain, heart, liver, kidneys, and other organs. Vitamin B1 participates in the conversion of carbohydrates and lipids into energy, and it is required for the synthesis of thiamine pyrophosphate, or TPP, a cofactor that is essential for a multitude of enzymes involved in energy production in the cell. Without TPP, the body would be unable to produce energy, leading to paralysis.
Which Diseases Are Associated with Vitamin B1 Deficiency?
Vitamin B1 deficiency can cause beriberi disease and Wernicke-Korsakoff syndrome. In addition, TPP deficiency may lead to neurodegenerative diseases as well as hereditary metabolic malfunction.
• Beriberi disease. The two major types of beriberi are wet beriberi and dry beriberi. Wet beriberi affects heart and blood circulation, while dry beriberi damages the nervous system. In extreme cases, it can cause paralysis. Symptoms of beriberi also include dementia, waddling, and foot edema.
• Wernicke-Korsakoff syndrome. Vitamin B1 deficiency can exacerbate Wernicke-Korsakoff syndrome, an alcohol-induced nerve-damaging disease. Symptoms include memory loss, jerky eyeball movements, disorientation, and a staggering gait. Alcohol abstinence may reverse the course of the disease. Untreated, it can lead to psychosis and even death.
What Are the Causes of Vitamin B1 Deficiency?
• Major causes of vitamin B1 deficiency are insufficient intake from foods, malabsorption, transport malfunction, increased demand, or excessive loss. Diseases and conditions that elevate the risk of vitamin B1 deficiency include alcoholism, AIDS, digestive tract disease, liver disease, and severe vomiting. People who are on hunger strike or suffer from anorexia are prone to vitamin B1 deficiency.
Prevention and Treatment of Diseases
• Treatment. Meta-analysis confirms that vitamin B1 can treat heart failure (74). Vitamin B1 may also be effective in Alzheimer’s disease (37), glaucoma (69), and cataracts (49).
• Prevention. Vitamin B1 may prevent cataracts (49) and type 2 diabetes (60).
Which Food Items Are Vitamin B1 Rich?
Vitamin B1–rich foods include beef, nuts, milk, oats, oranges, pork, eggs, and legumes. Vitamin B1–fortified foods include rice, spaghetti, breakfast cereals, bread, and flour. The recommended dietary allowance of vitamin B1 is only 1.5 mg, an amount readily obtainable from foods. However, vitamin B1 is water soluble; therefore, it cannot be stored in the body and needs to be replenished daily via food.
This list of vitamin B1–rich food items is adapted from information provided by the USDA.
| FOOD | PORTION | VITAMIN B1 CONTENT, MG | % DAILY REFERENCE VALUE |
|---|---|---|---|
| Pork | 3 ounces | 0.81 | 54 |
| Green beans | ½ cup | 0.21 | 14 |
| Brown rice | 1 cup | 0.19 | 13 |
| Walnuts | 1 ounce | 0.19 | 13 |
| Hyacinth beans | ½ cup | 0.17 | 7 |
| Oranges | 1 | 0.11 | 7 |
| Cantaloupes |
