Freezing and canning are food processing methods that provide the benefit of preventing
spoilage and preserving nutritional value. But much processed food is high
in added fat, sugar, and salt—all of which are deleterious to the food’s nutritional
value. For example, some fruits are packed in high sugar syrup, and some canned
vegetables are high in sodium. High sugar intake can increase the consumption of
calories, contribute to obesity, and indirectly increase cancer risk. Processed meat
has been classified as carcinogenic to humans. Another example of food processing
that is detrimental is the refining of grains, which both increases their glycemic
index and greatly lowers the amount of fiber and other compounds that may reduce
There is some evidence that highly processed foods may raise cancer risk. A five-year
study found that every 10% increase in ultra-processed foods (e.g., baked
goods, processed meats, sugary cereals) was associated with a 12% greater risk for
all cancers and an 11% increased risk of breast cancer.96 No significant link with
prostate or colorectal cancer was found.
Salt and pickling
Although diets that contain excessively large amounts of foods preserved by salting
and pickling increase the risk of stomach, nasopharyngeal, and throat cancer, the
levels of salt used in cooking and food processing in the U.S. do not appear to affect
Antioxidants, vitamins, and other dietary supplements
A diet rich in vegetables, fruits, and other plant-based foods may reduce the risk of
cancer, but there is little proof that dietary supplements can reduce cancer risk, and
some studies have found that certain supplements increased risk of cancer. Studies
of a large variety of dietary supplements, including vitamins A, C, D, E, and folate,
have not found that they lower cancer risk. Some studies have found an increased
risk of cancer and other diseases among those taking supplements. For example,
folic acid supplements may increase the risk of prostate cancer, advanced colorectal
polyps, and possibly breast cancer. The best way to get all vitamins is by eating
vegetables, fruits, and enriched whole-grain products. The role of vitamin D in
cancer and other health issues is the subject of much research, but the Institute of
Medicine concluded that outcomes related to cancer and other neoplasms, could not
be linked reliably with calcium or vitamin D intake.
The VITAL study was a high-quality, randomized, double-blind trial. It found that high doses of vitamin D (2000IU per
day or three times the RDA) taken for 5.3 years did not reduce the risk of invasive
cancers. Treatment effects did not vary with baseline levels of vitamin D, so
even people with low levels did not benefit. There was some indication that normal-
weight participants may have had a lower cancer incidence and that starting
after two years, those taking vitamin D had a lower death rate than those taking a
placebo. These secondary endpoint results are less reliable and should be considered
a finding that needs additional study.
Although there is some evidence that calcium supplements reduce the risk of colorectal
cancer, a high calcium intake, whether through supplements or food, has
also been linked with an increased risk of prostate cancer. Men should try to get, but
not exceed, recommended levels of calcium, mainly through food sources.
Coffee, tea, and cancer
There is no sound evidence that coffee, tea, or caffeine increases or decreases the
risk of cancer.
The best studies have not found that fat intake increases cancer risk, or that lowering
fat intake reduces cancer risk.
Genetically modified foods
Most soybeans and corn grown in the U.S. come from seeds that have been modified
to resist herbicides, and in the case of corn, modified to make a natural insecticide.
At present, there is no proof that the genetically modified foods currently
on the market are harmful to human health or that they either increase or decrease
cancer risk. However, some scientists suggest that additional studies are needed to
assess possible long-term health effects.
There is no evidence that irradiation of foods used to kill harmful germs in or on
foods to extend their shelf life causes cancer or has harmful health effects. The radiation
of foods does not make them radioactive.
This blog presents opinions and ideas and is intended to provide helpful general information. I am not engaged in rendering advice or services to the individual reader. The ideas, procedures and suggestions in that are presented are not in any way a substitute for the advice and care of the reader’s own physician or other medical professional based on the reader’s own individual conditions, symptoms or concerns. If the reader needs personal medical, health, dietary, exercise or other assistance or advice the reader should consult a physician and/or other qualified health professionals. The author specifically disclaims all responsibility for any injury, damage or loss that the reader may incur as a direct or indirect consequence of following any directions or suggestions given in this blog or participating in any programs described in this blog or in the book, The Building Blocks of Health––How to Optimize Your Health with a Lifestyle Checklist (available in print or downloaded at Amazon, Apple, Barnes and Noble and elsewhere). Copyright 2021 by J. Joseph Speidel