Beta Carotene in a nutshell
Beta carotene is used by the body to make vitamin A. It’s a bright orange pigment that gives carrots their color, and is a powerful antioxidant.
Best source of Beta Carotene for Juicers
Beta carotene can be obtained from carrots, kale, apricots, parsley, spinach, watercress, mangoes, broccoli and romaine lettuce. However, it really is hard to become deficient in beta carotene.
What Is Beta-Carotene?
Beta-carotene, the orange pigment that is particularly abundant in carrots, is a provitamin, a substance the body uses to make a vitamin. Unless you consume large amounts of liver, cod liver oil, butter, and cream, you get most of your vitamin A from beta-carotene.
Alternative names: Beta-carotene; 1,1′-(3,7,12,16-Tetramethyl-1,3,5,7,9,11,13,15,17-octadecanonaene-1,18-diyl)bis[2,6,6-trimethylcyclohexene].
Beta-carotene is a reddish-orange pigment abundant in carrots and in orange-colored fruits. Plants make beta-carotene and related pigments to protect themselves from excessive sunlight.
Beta-carotene absorbs all the wavelengths of visible light except its shade of orange. It is especially useful for protecting the plant from free radicals of oxygen released by the action of infrared light, and it is especially important for the survival of the roots and fruits that contain it when the weather is hot and dry.
Beta-carotene is not water-soluble. In plants, it tends to accumulate in fibers that humans have trouble digesting. This plant chemical is soluble in industrial solvents such as hexane, which is boiled off to leave a beta-carotene powder for use as a dye or in making supplements. The human body can more easily absorb beta-carotene digested from food that is mixed with a small amount of fat.
Humans and some other animals have an enzyme called beta-carotene 15,15′-monooxygenase that can convert a molecule of beta-carotene into two molecules of the form of vitamin A known as retinal. Although pre-formed vitamin A is found in cod liver oil, cream, butter, and very few other foods, most of the vitamin A in human nutrition is actually consumed as beta-carotene from plant food sources.
It's Hard to Absorb Beta-Carotene
It's not easy for the human body to get beta-carotene from food. Most of the plant foods that are rich in beta-carotene are also high-fiber. Microscopic beta-carotene crystals are attracted to proteins dispersed through plant fiber. The fruit or vegetable containing these beta-carotene crystals has to be thoroughly chewed to release the crystals.
Even if food is chewed well and mixed with saliva, it still has to be digested in the stomach. People who have low levels of stomach acid often are not able to digest the proteins bound to beta-carotene to release the beta-carotene for further processing in the small intestine. People who are over 60 often have a condition known as hypochlorhydria, or deficient stomach acid, and using a medication for heartburn can eliminate 99.999% of the acid in the stomach, causing proteins that form complexes with beta-carotene to pass through undigested.
It's also difficult for the small intestine to absorb beta-carotene. Absorption of beta-carotene takes place in the uppermost section of the small intestine, which is known as the duodenum. The receptors that absorb this plant nutrient also absorb vitamin E and lutein. If the meal is high in vitamin E or a vitamin E supplement has been taken with the meal, or if the meal is high in lutein or a lutein supplement has been taken with the meal, the receptors in the lining of the duodenum will not be available to absorb beta-carotene.
Beta-carotene has to “seep” into these receptors through tiny globules of fat known as mycelles. If the meal does not contain at least 3 to 5 grams (1/2 teaspoon to a teaspoon) of some kind of fat, the beta-carotene will just flow down through the rest of the intestinal tract unabsorbed. And if the meal is high in fiber, the fiber will “clump” with the fat and beta-carotene will be flushed away.
There is even a minimum amount of beta-carotene required for any of the vitamin to go into the bloodstream. At least 100 milligrams (about 160,000 IU) of beta-carotene is the “critical mass” needed for the absorption process to work at peak efficiency. Much less than about 10 milligrams (16,000 IU) of beta-carotene may not be absorbed at all.
The process of absorbing beta-carotene takes several days. The lining of the small intestine stores some of the beta-carotene absorbed from a meal to compensate for the possibility of not getting more beta-carotene later. If the lining of the small intestine is irritated and the lining sloughs off, the beta-carotene is lost.
Some of the beta-carotene absorbed into the lining of the intestinal wall is quickly converted into vitamin A. The rest of the beta-carotene absorbed into the bloodstream “hitches a ride” on very low-density lipoprotein, also known as VLDL cholesterol. This form of cholesterol is slowly broken down into low-density lipoprotein (LDL cholesterol) and high-density lipoprotein (HDL cholesterol). Riding through the bloodstream on cholesterol, beta-carotene may be stable in the human body for as long as 4 or 5 months.
Cooking Makes a Difference, and in a Good Way
It has become de rigueur to think of raw vegetables as always being superior in nutritional content, but that's not the case with beta-carotene. Plants make beta-carotene as a long, straight, trans- molecule, with side chains appearing in a regular fashion on opposite side of the molecule. Cooking transforms beta-carotene into a curled-up short molecule with cis- (same side) bonds, something like a molecular ball.
It turns out that the curled up form of beta-carotene has a lot easier time being deposited into the tissues than need it than the long-chain form beta-carotene. Beta-carotene from cooked foods accumulates in the breasts and ovaries in women and in the fatty tissue and adrenal glands of both sexes, giving them antioxidant protection. Beta-carotene from raw foods and synthetic beta-carotene supplements raises concentrations in the bloodstream higher and faster—but it isn't the bloodstream that needs antioxidant protection.
This is the reason several epidemiological studies have found that eating foods that are high in beta-carotene protects against cancer, atherosclerosis, and other forms of cardiovascular disease, while taking synthetic beta-carotene supplements has not effect or even increases the rates of disease. When it comes to beta-carotene, it's always best to eat foods rather than to take supplements. And if you do take supplements, it's better to take mixed carotenoids, a plant extract that contains not just beta-carotene but other related compounds that perform related tasks.
What Happens When We Don't Get Enough Beta-Carotene?
Strictly speaking, there is no such thing as a beta-carotene deficiency. Our bodies can make vitamin A from beta-carotene or we can get vitamin A from certain high-fat dairy products and fish oils or from supplements. If you aren't downing a daily dose of cod liver oil and if you eschew real cream and butter, however, you need to get your vitamin A from the beta-carotene in plant foods.
It's not hard to get enough beta-carotene if you eat carrots at least occasionally. Eating carrots just once a month can make a significant difference in cancer protection, particularly in the case of mesothelioma. But carrots are not the only food that is rich in beta-carotene.
- A 3-1/2 oz (100 gram) serving freeze-dried red peppers contains 42,886 micrograms of beta-carotene.
- A 3-1/2 oz (100 gram) serving dehydrated carrots contains 33,954 micrograms of beta-carotene.
- A 3-1/2 oz (100 gram) serving raw grape leaves contains 16,193 micrograms of beta-carotene.
- A 3-1/2 oz (100 gram) serving sweet potato chips or fries contains 14,204 micrograms of beta-carotene.
- A 3-1/2 oz (100 gram) serving baked sweet potato contains 11,508 micrograms of beta-carotene.
- A 3-1/2 oz (100 gram) serving canned carrot juice contains 9,304 micrograms of beta-carotene.
- A 3-1/2 oz (100 gram) serving raw kale contains 9,246 micrograms of beta-carotene.
- A 3-1/2 oz (100 gram) serving cooked kale contains 8,824 micrograms of beta-carotene.
- A 3-1/2 oz (100 gram) serving boiled carrots contains 8,383 micrograms of beta-carotene.
- A 3-1/2 oz (100 gram) serving raw carrots contains 8,285 micrograms of beta-carotene.
- A 3-1/2 oz (100 gram) serving boiled, previously frozen spinach contains 7,035 of beta-carotene.
- A 3-1/2 oz (100 gram) serving canned, unsweetened pumpkin contains 6,941 of beta-carotene.
- A 3-1/2 oz (100 gram) serving canned carrots contains 5,941 of beta-carotene.
- A 3-1/2 oz (100 gram) serving canned spinach contains 5,881 of beta-carotene.
- A 3-1/2 oz (100 gram) serving canned mixed vegetables contains 5,669 of beta-carotene.
- A 3-1/2 oz (100 gram) serving raw spinach contains 5,626 of beta-carotene.
- A 3-1/2 oz (100 gram) serving boiled, previously frozen turnip greens contains 5,167 of beta-carotene.
- A 3-1/2 oz (100 gram) serving pumpkin pies contains 4,751 of beta-carotene.
- A 3-1/2 oz (100 gram) serving boiled, previously frozen peas and carrots contains 4,725 of beta-carotene.
- A 3-1/2 oz (100 gram) serving raw garden cress contains 4,125 of beta-carotene.
- A 3-1/2 oz (100 gram) serving raw beet greens contains 3,974 of beta-carotene.
- A 3-1/2 oz (100 gram) serving boiled Swiss chard (silverbeet) contains 3,652 of beta-carotene.
- A 3-1/2 oz (100 gram) serving baked acorn squash contains 2,793 of beta-carotene.
- A 3-1/2 oz (100 gram) serving boiled pak-choi (Chinese cabbage) contains 2,549 of beta-carotene.
- A 3-1/2 oz (100 gram) serving dried apricots contains 2,163 of beta-carotene.
There are also small amounts of beta-carotene (100 to 200 micrograms) in butter, egg yolks, yellow cheeses, and certain luncheon meats, as well as in liver, brain, and organ meats of commonly eaten animals. There is a huge amount of beta-carotene in the Vietnamese vegetable gac (used to make a reddened rice dish for Lunar New Year) and in Vietnamese hearts of palm, but these vegetables are hard to find outside of Southeast Asia.
How much beta-carotene do you need to consume in a given day? The high range of beta-carotene consumption from food, associated with the greatest health benefits, is about 7 mg or 7,000 micrograms per day. That's about just one or two servings from any vegetable on the list above. If you skip a day, that's OK, as long as you get an average of 7,000 micrograms of beta-carotene per day.
Making Health Conditions Better (or Worse) with Beta-Carotene
Advocates of nutritional supplementation expressed disbelief in 1994 when the Finnish researchers running the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study found that taking synthetic beta-carotene actually raised the lung cancer risk of smokers and asbestos workers. They also took exception in 1996 when the Beta-Carotene and Retinol Efficacy Trial in the USA also found that taking synthetic beta-carotene raised the risk of lung cancer in smokers. Similar results have been found in several dozen studies released as recently as December of 2011.
It just could not be that a nutrient (one they sold) could possibly harm anyone. Yet it apparently does. How can this be?
Synthetic beta-carotene is a long, straight-chain molecule that tends to travel through the bloodstream without being absorbed into tissues. When it comes into the body, however, it keeps receptors from absorbing another helpful plant nutrient, lutein, and also probably reduces that absorption of lycopene, beta-cryptoxanthin, lutein, and alpha-carotene.
Synthetic beta-carotene doesn't reach its target tissues and it keeps other helpful antioxidants out of circulation. Is it any wonder that clinical trials fail to find any benefit from taking it?
On the other hand, natural beta-carotene is associated with lower rates of cancer, atherosclerosis, arthritis, and even sunburn. So what can you do if you want the benefit of natural beta-carotene but you don't like to eat carrots, kale, cress, and acorn squash?
The answer is a natural nutritional supplement called mixed carotenoids. Made from a kind of algae called Dunaliella, mixed carotenoids provide not just beta-carotene but also alpha-carotene, cryptoxanthin, and zeaxanthin. Processing produces beta-carotene in both its cis- and trans- forms that can enter target tissues while also helping fight free radicals in the bloodstream itself.
What are the specific conditions you can treat with beta-carotene?
Taking 25,000 IU of mixed carotenoids per day is the best way to gain all the protective benefits of beta-carotene. It's also a good way to treat inflammatory bowel disease. The unique combination of antioxidants in Dunaliella relieves inflammation and irritability in the lining of the bowel.
Taking mixed carotenoids for 30 days before you to go the beach reduces the risk of sunburn. Taking mixed carotenoids also prevents the formation of oxidized LDL cholesterol (the kind that causes arterial plaques) in diabetics.
The primary use of any kind of beta-carotene supplement, however, is for prevention. If you use beta-carotene supplements to maximum effect, you will never know which diseases they prevented. And that is always the best result of any nutritional supplement program.
Beta-Carotene in Fruit and Vegetable Juices
Beta-carotene is the plant pigment that makes carrots orange. A versatile antioxidant that the human body can use to make vitamin A, beta-carotene is both an important nutrient and a source of deep orange color for apple, apricot, mango, papaya, peach, and mixed vegetable juices. In Europe, additional beta-carotene is sometimes labeled E160a.
Most of the beta-carotene used in commercial fruit and vegetable juices is extracted from carrots. It's less expensive to use carrots as a source of beta-carotene than it is to create beta-carotene through chemical processes. Beta-carotene from carrots can be added to organic juice products, although vegans may want to know that some European manufacturers stabilize beta-carotene with beef or fish protein. This should be but may not be listed on the label.
It's hard to get too much beta-carotene. In the most extreme cases of overindulgence (eating 8 to 10 carrots or drinking 4 or 5 glasses of carrot juice per day), beta-carotene can temporarily stain the skin. It's safe and even healthy for smokers to consume both carrot juice and fruit and vegetable juices colored with beta-carotene, but they should limit their consumption of juices colored with added beta-carotene to one 8-ounce (240 ml) glass per day, to ensure getting a variety of antioxidants. Carrot oil is an especially concentrated form of beta-carotene with all its cofactors that is better for smokers than beta-carotene alone.