Over the past twenty years, scientists have been able to link the intake of certain food groups with specific human diseases, including prostate cancer.
Because of advancements in technology the following questions can now be answered.
- Which foods have the highest association with development and progression of prostate cancer in men?
- What chemical components in those high-risk food groups are attributable to the risks?
- How does a specific chemical component from a high-risk food increase the risk of prostate cancer in men?
- What dietary modifications could be made that would realistically have the possibility of reducing the risk?
Any organ whose growth and function are under hormonal control will become malignant from excessive hormonal stimulation.
Based on the science of endocrinology, prostate cancer is defined as a hormonal imbalance and usually develops in men in their sixties or older. A time at which, growth and reproductive hormones should be declining. Thus, any dietary components that could stimulate a hormonal pathway could have some effect on risk of developing prostate cancer.
Although, a large variation in the timing of detection exist in one’s life, the fatality from prostate cancer appears to consistently occur later in life. Based on these observations, it is very plausible that prostate cancer more accurately reflects the total accumulation of dietary habits over one’s lifetime. Since, prostate cancer is not inherited nor the result of an infection.
Most countries has a governmental department that is responsible for keeping a historical record of the incidence, types, and rates of mortalities, and a record of all foods consumed and exported. The following information was taken from those historical records.
In 2002, an epidemiological study took place on the incidence and mortality of testicular and prostate cancer and their relation to world dietary practices. This study analyzed data spanning a thirty-year period and covered 5 continents, 42 countries, and 193 populations, and only data that could be confirmed was used. Eight countries were excluded for lack of documentation. The food groups studied were meats, dairy, and plants. Meats included beef, pig, poultry, and goat. Dairy included eggs, butter, and milk from dairy. Plants included cereals, beans, peas, fruits, vegetables, raw tomatoes, coffee, tea, and alcohol.
Among the sixteen food items that were examined, milk had the strongest correlation with the mortality rate of prostate cancer, followed by coffee, cheese, and fat from meats. Cheese was found to have the strongest association with testicular cancer. Raw tomatoes had an insignificant association while cereals had the strongest favorable association.
Milk also contained considerable amounts of female sex hormones such as estrogen, because commercial production of milk is always from pregnant cows. The authors remarked that man is the only mammal on earth that consumes milk after weaning.
As far as I am aware, the suspicion about milk and its association with human disease first surfaced during the 1970s, and again in the 1980s, in two earlier international comparisons of cancer mortality rates with the per capita consumption of foods. In those studies, the national rates of prostate cancer correlated directly in 32 countries with the per capita consumption of milk.
In 1998, analysis of data taken from the Health Professional Follow-Up Study in the United States consisted of the following: 47,781 male health professionals with no history of cancer were followed and studied for a period of 8 years. The study group consisted of only physicians, dentist, pharmacist, and veterinarians, between the ages 40-75 years old. Dietary intake and related diseases were assessed and recorded every two years. Between 1986 and 1994 prostate cancer was identified in 1,262 individuals, based on medical and pathology records.
This study consisted of a group of professionals inclined to be more health conscious, they drank less, smoked less, were more physically active, and took supplements. Eighty-three percent of the milk consumed was from non-fat or low-fat milks. When questioned about food choices the majority responded that dairy was chosen because of its high calcium content, and low-fat choices believing they were healthier because of less fat.
However, contrary to the belief at that time the highest risk for cancer has been found in the individuals who consumed two or more glasses of milk per day compared none, and the risk were actually higher in individuals consuming non-fat milk.
High calcium intake from dairy and supplements has been independently associated with the risk of prostate cancer. The risk association with calcium from supplements, independent of the risk association of calcium from dairy, strongly indicates that calcium is one component in dairy that plays a contributing factor in the risk.
A study in 2007 found that men who consumed 2000 mg/ day of calcium had a five-fold increased risk of developing prostate cancer compared to men who consumed only 500 mg/day. Another study found a high calcium intake was associated with a higher risk of advanced and fatal prostate cancer, compared with men whose long-term calcium intake was below 700 mg/day. In 2008, a study group found an increase in risk of prostate cancer, but only, with the calcium from dairy. There was no association of prostate cancer with calcium from non-dairy foods.
A place to start understanding calcium’s effect on cancer is to first notice that milk contains exceptionally higher levels of both calcium and phosphorus when compared to all other food groups. One cup of whole-milk contains 276 mg of calcium which equals 28% of the daily recommended amount, and 205 mg of phosphorus equal to 29% of its recommended amounts.
Thus, the calcium and phosphorus content from dairy alone will contribute more calcium and phosphorus to a daily diet than any of the other foods groups.
The problem stems from the experiments that have shown high intakes of both calcium and phosphorus are capable of inhibiting the kidney’s secretion of the metabolically active, hormonal form of vitamin D. Vitamin D has been shown to suppress the hormonal stimulatory effects involved in the growth of cancerous cells, and is an anti-cancer agent.
Thus, calcium and phosphorus are two components in milk that contributes to risk of prostate cancer by down regulating the kidney’s production of vitamin D, thereby interfering with the metabolism of the vitamin D receptor sites found in prostate cells.