Search for wellness enhancements with nutrition, supplements, and exercise. We help you reduce medication dependence and achieve ideal health.
Cancer Prevention
Assessment and Plan: Cancer Prevention Possibilities
There are especially strong genetic links seen between family members with colorectal cancer and breast cancer. (1)
Avoid smoking- DNA damage by carcinogens in tobacco may lead to lung cancer, bladder cancer and other cancers. Heterocyclic amines formed in meats heated over 180 degrees Celsius (about 400 degrees Fahrenheit for extended periods) are linked to breast, stomach and colon cancer in epidemiological studies. Liver cancer risk is elevated in patients with hepatitis infection exposed to aflatoxin produced by mold in foods originating from Asia and Africa. (2)
Compared to non-active participants, an increase in physical activity resulted in a 14% decreased risk for all-site cancer among men, a 16% decrease risk for lung cancer and a 15% decrease for cancer mortality especially in younger patients. Among women, they reported no association between physical activity and lung cancer incidence but for women who had lung cancer and were physically active had a 31% decreased risk of lung cancer mortality compared with women who were not physically active. (3)
A low fat/high fiber diet and an exercise program appears to reduce several serum markers for breast cancer including estrogen, obesity, insulin and insulin-like growth factor-I (IGF-I), making the blood less hospitable to cancer cells. (4,5)
The consumption of 5 or more daily servings of fruits and vegetables is recommended by “National Cancer Institute’s Five-A-Day for a Better Health program” and “Canada’s Food Guide for Healthy Eating.” High blood concentrations of beta-carotene and other carotenoids including plant pigments found in carrots, sweet potatoes, spinach, kale, collard greens, papaya, bell peppers, tomatoes, have been linked to a lower risk of cancer, especially lung, mouth, throat, and cervical cancers. A blood beta-carotene concentration less than 0.28 micromol/L has been linked with a higher risk of several cancers, while a concentration of more than 0.28 to 0.37 micromol/L have been associated with a reduced risk of several cancers in prospective blood concentration studies. Eating a variety of 5 fruits and vegetables per day provides the individual with about 5.2 to 6 mg/day of food based beta-carotene. This allows plasma carotenoid levels to rise above a range represented in studies which were associated with a lower risk of cancer and all-cause mortality compared to those with a lower food based carotenoid levels. (6)
According to Martini et al in the University of Minnesota Cancer Prevention Research Unit Feeding Studies, an intake of 5 mg per day of beta carotene was required to establish beta carotene levels to a plasma level of 0.37 umol/L. When food based beta carotene was consumed in amounts over 42 mg per day, levels increased to 0.83 umol/L. (9)
It is important to note that taking beta carotene in oral supplement form is advised against. One study, the Beta-Carotene and Retinol Efficacy Trial (CARET), was stopped early because it showed that beta-carotene/vitamin A takers who were heavy smokers, ex-smokers or asbestos workers were showing a 28% increased risk of lung cancer in smokers (versus placebo) and a 17% more likely chance of dying, mostly of lung cancer or heart disease. (8)
The U.S. Preventive Services Task Force (USPSTF) recommends against the use of beta-carotene supplements, alone or in combination. According to the USPSTF, the is insufficient evidence to recommend for or against the use of vitamins A, C, or E supplements or multivitamins with folic acid or antioxidant combinations for the prevention of cancer or cardiovascular disease (12). Beta-carotene supplements are not advised among healthy individuals (6). Intake of vegetables containing beta carotene was associated with a lower risk for all causes of death including cancer but no benefit was seen with taking beta-carotene supplements (7). An increased risk of mortality was associated with use of beta-carotene and vitamin E supplements (11).
Ensure good nutritional status with calcium and vitamin D. Lappe JM et al concluded that improvement of nutritional status with calcium and vitamin D significantly lowered cancer risk in post-menopausal women. (13)
Calcium intakes of at least 1180 mg per day whether from dietary calcium intake or calcium from supplements may reduce the risk of colorectal neoplasia and the recurrence of colorectal adenomas (14-16).
For the subject of calcium and prostate cancer, the analysis of the data becomes more complicated as more studies are included. Rodriguez C et al found that the intake of calcium over 2000 mg per day in the form of dietary and supplement intake was associated with a moderate increase in risk of prostate cancer (17). Chung et al also found that a number of studies reported that high calcium intakes were associated with an increased risk of prostate cancer (18). Huncharek M et al found an opposing outcome that as calcium intake from food increased, the risk of prostate cancer decreased across all races (19). Butler LM further complicated the understanding of the calcium and prostate cancer link when the study outcome found that moderate intakes of calcium from vegetables resulted in a moderately higher prostate cancer risk for subjects with a body mass index below 22.9 (20). Therefore, as an older male with the goal to reduce prostate cancer risk, an approach of maintaining an adequate (but not excessive) calcium intake from food is supported by the majority of the research but calcium supplements should be avoided by older men until further research is done.
Adequate calcium intake in premenopausal women appears to be associated with a decreased risk of breast cancer (21).
Michaëlsson K et al found a clear U-shaped curve when looking at the relationship between vitamin D levels and all-cause mortality along with cancer-related mortality, meaning the risk of mortality was significantly increased at both low and high blood levels of vitamin D. In the study, the range with the lowest mortality was about a vitamin D concentration of 24 to 34 ng/ml (60 to 85 nMol/L), which approximately translates to a vitamin D dose of 2000 IU/d. In general, the biggest drop in overall death rates were seen when subjects went from being vitamin D deficient to reaching adequate levels. However, too much vitamin D translated into a gradual increase of mortality rate with cancer deaths rising significantly for the highest levels of vitamin D intake. Overall mortality was increased by 50–60% among subjects in the lowest 10% and highest 5% of the vitamin D distribution. The ideal vitamin D dose according to findings in this study is 2000 IU per day for adults. (22)
Recently, the dose of vitamin D from the current standard of 400–600 IU per day was increased to 1000 IU per day because it may lower the future risk of cancer in women older than age 55 who do not get adequate vitamin D from sun exposure or diet. (24)
Loria and colleagues found an association between low blood ascorbate (vitamin C) levels and an increased risk of dying overall and from cancer, among men. No link between mortality and ascorbate levels were found among women. (25)
An analysis, was conducted on 19,496 men and women, ages 45 to 79, in the U.K. Death rates were significantly lower among those with higher blood ascorbic acid levels. Those with the highest ascorbic acid levels had half the risk of dying from all causes combined. Additionally, a 20 micromol/L increase in blood ascorbic acid concentration, the same as a 50 g per day increase in fruit and vegetable intake, was associated with about a 20% reduction in risk of all-cause mortality. (26)
Among healthy individuals, the recommended daily intake of vitamin C is 75 mg for women and 90 mg for men. Vitamin C has an upper tolerable level set at 2 grams per day set by the USDA has been shown to be safe but higher doses cause gastrointestinal side effects. (27)
Carr and Frei recommended a higher vitamin C intake of 90-100 mg per day to avoid chronic diseases. They found that low intake of vitamin C was related to an increase in cancer mortality. Vitamin C was inversely related to cancer mortality in elderly women but not in men. (50)
Loria et al found a similar conclusion of an increase in cancer mortality among men but not women with low vitamin C levels. Loria found that the vitamin C intake corresponding to the higher risk of mortality in men was less than or equal to 60 mg per day. (25)
A large cohort study in China on 29,584 adults at high risk of esophageal and stomach cancers who were given the supplements 50 mcg selenium, 30 mg vitamin E, and 15 mg beta-carotene found that treatment led to a decrease in mortality from all causes, cancer overall, and gastric cancer. There have been no other studies that have shown similar results (28). An increased risk of mortality was associated with use of beta-carotene and vitamin E supplements in other research (11).
A double-blind, randomized, placebo-controlled trial of 1,312 patients basal cell cancers (BCC) or squamous cell cancers (SCC) followed for over 6 years showed that 200 mcg of selenium did not lower skin cancer incidence and may increase the risk of BCC (by 10%) and SCC (by 14%) compared to placebo. The results did show that total cancer incidence was decreased by 37% (77 in the selenium group compared to 119 in the control group), total cancer mortality was decreased 50% (29 in the selenium group compared to 59 in the placebo group), and prostate cancer incidence was decreased by approximately 50% compared to placebo. These findings have not been confirmed with other research (29).
Red meat consumption has been found to be associated with increased cancer risk of the oral cavity and pharynx, esophagus, larynx, stomach, colorectum, lung, breast, prostate, bladder, and kidney. Lamb was also associated with increased cancer risk. Processed meat was also linked to an increased risk of cancers of the esophagus, larynx, stomach, colorectum, lung, and breast (30).
A study from Italy found that red meat intake of at least 7 times per week had a higher incidence of cancers of the stomach, colon, rectum, pancreas, bladder, breast, endometrium, and ovaries. In this study, red meat was not connected to cancers of the oral cavity, pharynx, esophagus, liver, gallbladder, larynx, kidney, thyroid, prostate, Hodgkin’s disease, non-Hodgkin’s lymphomas and multiple myeloma. (31)
A meta-analysis with 7 studies and 124,706 participants found a statistically reduced cancer incidence of 18% and a lower all-cause mortality in vegetarians than non-vegetarians (32).
A 12-year study on 61,566 subjects showed that cancer among meat eaters was 3.8%, among fish-eaters was 0.5%, and among vegetarians was 1.3%. The study found that compared to meat-eaters, vegetarians had a 53%, 45% and 74% reduced risk in bladder, leukemia/lymphoma, and stomach cancers, respectively. Vegetarians were 12% less likely, and fish eaters were 18% less likely than meat eaters to develop all types of cancer combined (33).
Premenopausal women with an increased intake of lutein and zeaxanthin (both carotenoids), vitamin A, and beta-carotene from food or 5 servings of fruits and vegetables per day was associated with a moderate reduction in breast cancer risk especially in those with a family history (34).
A literature review of 206 human studies and 22 animal studies by Steinmetz, K. A.et al showed that a high consumption of fruits and vegetables decreased the cancer risk of the stomach, esophagus, lung, oral cavity, pharynx, endometrium, pancreas, and colon. The most protective foods against cancer included raw vegetables, followed by allium vegetables (onion, garlic), carrots, green vegetables, cruciferous vegetables (broccoli, cauliflower, Brussels sprouts, kale, cabbage), and tomatoes (35).
A review of epidemiologic studies found that the higher the consumption of brassica vegetables the lower the risk of cancer especially for cancers of the lung and digestive tract (36).
A significant reduction in risk for esophageal, lung, stomach and colorectal cancers was seen with both fruit and vegetable consumption and there was a reduced risk of bladder cancer seen with fruit consumption but not vegetables (37).
Men who consumed at least 6 servings of fruits and vegetables per day had a 55% reduced risk of renal cell cancer (RCC), and vitamins A and C were found to be inversely associated with RCC (38).
A significant reduction in all-cause mortality in women who consumed higher lignan levels (the lowest risk of dying was seen in women consuming >318 mcg per day of lignans. These same women were far less likely to die of breast cancer. There was also a lower all-cause mortality seen with intake of dried beans. For the women enrolled in this study, the main food sources of lignans were dark bread, peaches, coffee, broccoli and winter squash but the source known to have the highest amount of lignans are flax seeds (39).
The Preventive Services Task Force (USPSTF) and most physicians do not recommend aspirin solely for colorectal cancer prevention because higher doses than those used for cardiovascular disease prevention are required to accomplish this goal. The risk of gastrointestinal bleeding with (nonsteroidal anti-inflammatory drugs) NSAIDs and aspirin outweigh the benefits of colorectal cancer prevention. (41) Bardia A et al did however determine as part of a cohort study that cancer incidence and cancer mortality was reduced even in patients that used aspirin infrequently compared to those that never used it. In that study, women with the lowest all-cause mortality took aspirin 2-5 times per week. There was no statistically significant impact on cancer incidence or mortality among women who used non-aspirin NSAIDs, compared to those who did not. (42) The safest approach is that aspirin should not be used specifically for cancer prevention, but if aspirin is used for cardiovascular disease prevention, there may be a small added benefit of cancer prevention.
Whey protein used for cancer prevention requires further investigation in clinical trials.
Maintenance of ideal bodyweight may be ideal for the prevention of cancer related mortality. A positive linear trend in death rates with increasing body mass index has been observed for most types of cancer. Men in the highest body mass index group (>40) were 52% more likely to die of all cancers than men in the lowest body mass index group (18.8 – 24.9). For women the risk was even greater, at 62%. The conclusion of the study was that the proportion of all deaths from cancer attributable to overweight and obesity in U.S adults over 49 years old may be a high as 14% for men and 20% for women. The author expressed that more than 90,000 deaths per year from cancer might be avoided if everyone in the adult population could maintain a body mass index under 25 throughout life. (45)
Agaritine has been described in some studies as potentially harmful and a factor that may lead to cancer, however, studies using mushrooms and mushroom extracts have not provided significant evidence of the harmful effects of agaritine or mushroom consumption (46,47). If concerned, this possibility should be avoided by cooking mushrooms which destroys the agaritine. Mushrooms have also shown some evidence of breast cancer prevention but there is currently not enough evidence to support intake of large amounts of raw/cooked mushrooms, or supplements containing agaritine for prevention of breast cancer. See the agaritine section.
In vitro studies on Indian gooseberry has shown potentially promising applications in cancer prevention but there have not been any clinical trials to evaluate this possibility (49).
