| Other members of the antioxidant carotene family include cryptoxanthin, alpha-carotene, zeaxanthin, lutein (p. 308), and lycopene (p. 308); however, unlike beta-carotene, most of these nutrients do not convert to significant amounts of vitamin A.
How Do Natural and Synthetic Beta-Carotene Differ?
Most, but not all, beta-carotene in supplements is synthetic, consisting of only one molecule called all trans beta-carotene. Natural beta-carotene found in food is made of two molecules—all trans beta-carotene plus 9-cis beta-carotene. |
Bill Sardi
See book keywords and concepts |
 Beta carotene: good or bad?
Cancer doctors are quick to say beta carotene increases the risk of lung cancer among smokers. But the study they refer to only found that beta carotene was ineffective in smokers. [Journal National Cancer Institute 888: 1560-70, 1996] It didn't significantly raise the risk for lung cancer, despite what you may read or hear elsewhere. Inexplicably, cancer researchers now suggest a derivative of beta carotene may be helpful in treating or preventing lung cancer, but claim that beta carotene itself is toxic! |
Tori Hudson, N.D.
See book keywords and concepts |
 For some time it was thought that exercise-induced amenorrhea in long-distance runners was associated with hypercarotenemia, but that association was disproved, and no difference in carotene levels was observed.11
I found no reference to amenorrhea or menstrual irregularities associated with taking carotene supplements, and, as of this writing, I don't believe amenorrhea has been reported as a side effect of beta-carotene ingestion. However, I will probably encourage women who are experiencing significant weight loss and amenorrhea to eat lesser amounts of carotene foods for the time being. |
Alan R. Gaby, M.D., Jonathan V. Wright, M.D., Forrest Batz, Pharm.D. Rick Chester, RPh., N.D., DipLAc. George Constantine, R.Ph., Ph.D. Linnea D. Thompson, Pharm.D., N.D.
See book keywords and concepts |
 Women with excessive carotene levels in their blood appear to be at higher risk of amenorrhea than women with normal levels,21' 22 and, while research has not shown high carotene levels to directly cause amenorrhea, they may constitute a contributing factor.23 In one preliminary study, women with high levels of both carotenes and amenorrhea had predominantly vegetarian diets, and reducing dietary intake of carotenes led to lower carotene levels and improvement in their amenorrhea. |
James F. Balch, M.D. and Mark Stengler, N.D.
See book keywords and concepts |
 Carotenoids (Carotenes)
Examples of carotenoids include beta carotene, alpha carotene, gamma carotene, beta zeacarotene, cryptoxanthin, lycopene, zeaxanthin, lutein, canthaxanthin, crocetin, cap-santhin).
Function: There are over 600 identified carotenoids. Approximately 50 act as precursors to vitamin A. Carotenoids are potent antioxidants, help with immune function, and are involved with the growth and the repair of tissues. |
Bill Sardi
See book keywords and concepts |
| Vitamin A versus beta carotene
Beta carotene isn't vitamin A; it converts to vitamin A on an as-needed basis, with excess amounts being stored in the skin. Foods like carrots, squash, pumpkin, cantaloupe and sweet potatoes provide exceptional amounts of beta carotene.
When animal products, such as butter, milk, fish and liver, are consumed, their beta carotene content has already been converted to vitamin A, so it is ready to use, and no liver conversion is necessary. |
Tori Hudson, N.D.
See book keywords and concepts |
| I found no reference to amenorrhea or menstrual irregularities associated with taking carotene supplements, and, as of this writing, I don't believe amenorrhea has been reported as a side effect of beta-carotene ingestion. However, I will probably encourage women who are experiencing significant weight loss and amenorrhea to eat lesser amounts of carotene foods for the time being. I would also be inclined to reduce their vitamin A and carotene supplementation if they were on high doses for some other medical reason.
Calcium. |
Alan R. Gaby, M.D., Jonathan V. Wright, M.D., Forrest Batz, Pharm.D. Rick Chester, RPh., N.D., DipLAc. George Constantine, R.Ph., Ph.D. Linnea D. Thompson, Pharm.D., N.D.
See book keywords and concepts |
| Women with excessive carotene levels in their blood appear to be at higher risk of amenorrhea than women with normal levels,21' 22 and, while research has not shown high carotene levels to directly cause amenorrhea, they may constitute a contributing factor.23 In one preliminary study, women with high levels of both carotenes and amenorrhea had predominantly vegetarian diets, and reducing dietary intake of carotenes led to lower carotene levels and improvement in their amenorrhea. |
Gale Maleskey
See book keywords and concepts |
 Carotene is also an effective cancer preventive, but not necessarily in the form of beta-carotene. carotene capsules that contain natural carrot oil are much better for preventing cancer than synthetic beta-carotene, says Dr. Brett. "In fact, there's some evidence to suggest that taking synthetic beta-carotene could actually increase your risk of getting cancer," she says. "I typically recommend taking 25,000 IU a day of carotene, or about five carrots' worth."
Immunity Boosters
In order to successfully ward off disease of any kind, your body needs a sound immune system. |
Bill Sardi
See book keywords and concepts |
| Beta carotene: good or bad? ... 141
Do they really want you to stop smoking? ... 142
Tax and smoke ... 142 New smokers needed ... 143 The tobacco industry... 143
A Frank Statement to Cigarette Smokers... 144 Tobacco additives... 146
Lung cancer rates, Japan ... 147
Smokers as pawns to industry: screening programs ... 148 Treatment for lung cancer... 148
Chemotherapy and antioxidants ... 149 Prevention ... 151
Vitamin D and lung cancer ... 151
Does beta carotene really increase the risk for lung cancer among smokers? ... 153
No corroboration ... 155
Rethinking beta carotene ... |
Abram Hoffer, PhD, MD, FRCP(C) and Dr. Jonathan Prousjy, DPHE, DSC, ND, FRSH
See book keywords and concepts |
 It is found in two forms, as retinol in animal foods and as carotene in plant foods primarily.
Over 400 carotenoids are known in nature. They are the colored pigments widely found in plants. Beta-carotene is the most abundant and best known. One molecule can be converted into vitamin A. Only about 10% to 50% of the beta-carotene consumed is absorbed. The amount changed to vitamin A depends upon the vitamin state of the body. If the body has enough vitamin A, no more beta-carotene will be converted into the vitamin. |
Tori Hudson, N.D.
See book keywords and concepts |
| Another group of researchers found elevated serum carotene levels in women with anorexia nervosa, but not in women with normal or abnormal menstrual function.7 It is thought that mobilization of fat stores secondary to weight loss might be responsible for hyper-carotenemia in women with anorexia nervosa.
In 1971, a small study examined six women with elevated serum carotene levels who had excessive intake of carrots or pumpkins. |
Prevention Magazine
See book keywords and concepts |
 Beta-carotene is not the only carotene found in squash. A related compound, called alpha-carotene, is also present, though in smaller amounts. "It's very similar chemically to beta-carotene, but there has not been a lot of work done on it yet," says Dr. Kestin.
Getting the Most
Shop for color. There's a huge variability in the amount of beta-carotene found in squash. It can range anywhere from about 0.5 milligram to about 5 milligrams, even in the same kind of squash.
As a rule, experts say, the darker the squash, the more beta-carotene it contains. |
Tori Hudson, N.D.
See book keywords and concepts |
| However, I will probably encourage women who are experiencing significant weight loss and amenorrhea to eat lesser amounts of carotene foods for the time being. I would also be inclined to reduce their vitamin A and carotene supplementation if they were on high doses for some other medical reason.
Calcium. One of the serious long-term consequences of amenorrhea due to premature ovarian failure or lower production of estrogen (hypothalamic amenorrhea) is a lower bone density and an increased risk for osteoporosis and fractures later in life. |
J. Robert Hatherill
See book keywords and concepts |
 Beta carotene may provide a counteroffensive for people who smoke, since levels of beta carotene are lower in smokers than in nonsmokers. When smokers take the same amount of beta carotene as nonsmokers, they still end up with lower blood levels of that vitamin, suggesting that smokers have a greater need for beta carotene and should take larger amounts.
Observers have noted that beta carotene seems to be its most potent against lung cancer. |
Ray D. Strand
See book keywords and concepts |
 Beta-carotene, along with all the different types of carotene, is also necessary to help prevent or slow down this process.
I want to build up the glutathione levels within the cell by giving the body its precursors—selenium, vitamin B2, N-acetyl-L-cysteine, and niacin. In the next chapter, you will also learn the importance of folic acid and vitamins B6 and B12 in reducing the risk of cardiovascular disease.
Again, all of these nutrients work together either to eliminate or to decrease the inflammation in the arteries. |
Sheldon Saul Hendler and David Rorvik
See book keywords and concepts |
 In the carotene and Retinol Efficacy Trial (CARET), smokers taking 30 milligrams of beta-carotene daily and 25,000 IUs/d of retinol were found to have a higher incidence of lung cancer when compared to the placebo group. It is at present unclear if there is a true link between increased lung cancer incidence in smokers taking beta-carotene supplements.
INTERACTIONS
DRUGS
Cholestyramine: Concomitant intake of cholestyramine and beta-carotene may decrease the absorption of beta-carotene. |
Ralph Moss, PhD
See book keywords and concepts |
 The Synthetic carotene Issue
The distinction between natural and synthetic supplements is controversial, but scientists have shown there can be important differences between the two. As noted, CARET participants were given a synthetic form of beta-carotene. This may have affected the results.
In 1989, Israeli researchers showed that natural beta-carotene contains a balanced mixture of chemicals. There is also a tenfold higher accumulation of natural beta-carotene in the livers of lab animals than of synthetic beta-carotene. |
Bryan Hanson, PhD
See book keywords and concepts |
 However, the carotenoids, compounds related to carotene, are of great interest as antioxidants (see Chapter 5). p-Carotene (see Figure 4.39) is a good example.
OH
FIGURE 4.38. Cardiac glycosides.
FIGURE 4.39. (5-Carotene, a tetraterpene.
SUGGESTED READING
All texts on organic chemistry or introductory biochemistry have sections devoted to each of the four classes of primary metabolites described in this chapter. They should be consulted for more detailed information.
Ball. P. (2001). Stories of the invisible: A guided tour of molecules. New York: Oxford University Press. |
Thomson Healthcare, Inc.
See book keywords and concepts |
 A note on the role of dietary retinol and carotene in human gastro-intestinal cancer. Int J Cancer 1981; 28(4) :421-424. 1981.
Muscat JE, Huncharek M. Dietary intake and the risk of malignant mesothelioma. Br J Cancer 73:1122-1125. 1996.
Nguyen ML, Schwartz SJ. Lycopene: chemical and biological properties. Food Technol 53(2):38-45. 1999.
Okajima E, Ozono S, Endo T, et al: Chemopreventive efficacy of piroxicam administered alone or in combination with lycopene with beta-carotene on the development of rat urinary bladder carcinoma after n-butyl-N-(4-hydroxybutyl)nitrosamine treatment. |
| Mayne ST, Janerich DT, Greenwald P, et al: Dietary beta carotene and lung cancer risk in U.S. nonsmokers. J Natl Cancer Inst 86(l):33-38. 1994.
Modan B, Cuckle H, Lubin F. A note on the role of dietary retinol and carotene in human gastro-intestinal cancer. Int J Cancer 1981; 28(4) :421-424. 1981.
Muscat JE, Huncharek M. Dietary intake and the risk of malignant mesothelioma. Br J Cancer 73:1122-1125. 1996.
Nguyen ML, Schwartz SJ. Lycopene: chemical and biological properties. Food Technol 53(2):38-45. 1999. |
Michael Pollan
See book keywords and concepts |
 This had the effeet of tinting the flour yellowish gray (the yellow is carotene) and shortening its shelf life, because the oil, once exposed to the air, soon oxidized—turned rancid. That's what people could see and smell, and they didn't like it. What their senses couldn't tell them, however, is that the germ contributed some of the most valuable nutrients to the flour, including much of its protein, folic acid, and other B vitamins; carotenes and other antioxidants; and omega-3 fatty acids, which are especially prone to rancidity. |
Alan R. Gaby, M.D., Jonathan V. Wright, M.D., Forrest Batz, Pharm.D. Rick Chester, RPh., N.D., DipLAc. George Constantine, R.Ph., Ph.D. Linnea D. Thompson, Pharm.D., N.D.
See book keywords and concepts |
| In one preliminary study, women with high levels of both carotenes and amenorrhea had predominantly vegetarian diets, and reducing dietary intake of carotenes led to lower carotene levels and improvement in their amenorrhea.24 Women vegetarians often rely heavily on soy foods as sources of protein, and a number of studies have found that increasing dietary intake of soy reduces levels of estrogen and progesterone in premenopausal women,25,26' 27' 28' 29,30 although some studies have not found these changes. |
Jack Challem
See book keywords and concepts |
 Studies of smokers and beta-carotene have shown contradictory effects, but a modest intake of this carotene (10,000 IU or 6 mg) in combination with other antioxidants, such as vitamins E and C, is likely to be helpful. There appears to be a threshold of benefits from beta-carotene in smokers, so the above dosage should not be exceeded.
In a study of street workers in Mexico City, regarded as the most polluted large city in the world, men were asked to take 75 mg of vitamin E, 650 mg of vitamin C, and 15 mg of beta-carotene or placebos daily for 2/4 months. |
Bill Sardi
See book keywords and concepts |
| Beta carotene (vitamin A)
The timing was perfect. The negative study about beta carotene supplements was released to the news media just prior to the vote in Congress on access to dietary supplements. It was April of 1994. The bogus study was published in the most prestigious of medical journals - the New England Journal of Medicine and its lead author was in Helskinki, Finland, where he wouldn't have to face tough questions from skeptics in the U.S. [New England Journal Medicine 330: 1029-35, 1994]
The headlines were startling, especially for dietary supplement users. |
Elaine Magee
See book keywords and concepts |
 Soy milk, regular, 1 c
40
10
140
Tofu, firm, 4 oz, uncooked
38
9
120
Textured soy protein, % c, cooked
35
11
59
Soy milk, light, 1 c
20
4
100
Isolated soy protein, V4 c
14
6
30
Soy concentrates, 1 oz, dry
12
17
94
CAROTENOID FAMILY
You may have heard news bites about a particular carotene, beta-carotene, in recent years. Well, it turns out that we probably should be inviting the whole family of carotenoids to dinner! Some researchers suggest that mixtures of carotenoids exhibit more antioxidant activity than each of the carotenoids does by itself. |
Bill Sardi
See book keywords and concepts |
| Q_ < u
Vitamins p 340-384
Beta carotene (vitamin A)... 340
Too Much Vitamin A Dangerous... 342
Vitamin A versus beta carotene ... 344
Vitamin A and cancer... 344 Vitamin Bl and cancer... 345 Niacin and cancer... 345
Niacin, oxygen and tumors... 346 Vitamin B6 and cancer... 346 Folic acid and cancer... 346
Folic acid conquers one type of cancer... 347
Human studies... 347
Folic acid and cervical cancer... 348
Folic acid and viral-induced cancer... 348
How much more evidence is needed? ... 349
How much folic acid? ... 349
Why no action? ... 350
Folic acid reversal... |
Abram Hoffer, PhD, MD, FRCP(C) and Dr. Jonathan Prousjy, DPHE, DSC, ND, FRSH
See book keywords and concepts |
| The carotene cleavage activity changes with each ovulation cycle, the highest activity occurring during the mid-ovulation stage. The proper ratio of carotene-to-retinol must be maintained to ensure proper corpus luteum function. Since the corpus luteum produces progesterone, inadequate corpus luteum function could have significant negative clinical effects on the health of the female reproductive system.
To prevent fertility issues, cysts, and PMS, it seems necessary to ensure an optimal daily intake of beta-carotene and other carotenoids. |
Thomson Healthcare, Inc.
See book keywords and concepts |
| Omenn GS, Goodman GE, Thornquist MD et al: Effects of a combination of beta carotene and vitamin A on lung cancer and cardiovascular disease. N Engl J Med; 334:1150-1155. 1996
Plummer M, Vivas J, Lopez G, et al. Chemoprevention of precancerous gastric lesions with antioxidant vitamin supplementation: a randomized trial in a high-risk population. J Natl Cancer Inst; 99:137-146; 2007
Powers S, Hamilton K: Antioxidants and exercise. Clin Sports Med; 18(3):525-536. 1999
Product Information: Lumitene® (beta-carotene). (Tishcon Corp., Westbury, NY, 1996. |
Email this page to a friend
