STUDY: Amino acid, when heated, helps form possible carcinogen

JOURNAL: Nature

AUTHORS:

ABSTRACT: Scientists have found a clue to the chemical reaction that may cause potato chips, french fries and other fried or baked starchy foods to build up high levels of a possible cancer-causing substance.

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COMMENTARY: The suspect is asparagine, a naturally occurring amino acid that, when heated with certain sugars such as glucose, leads to the formation of the worrisome substance acrylamide.

The Food and Drug Administration has made studying acrylamide’s risk and determining how to lower its levels in food one of its highest research priorities, according to a plan that agency officials were to discuss Monday with consumer groups and food manufacturers.

Canada’s government made the discovery about the suspect chemical reaction, and has ordered food manufacturers to look for ways to alter it and thus lower levels of acrylamide in food. Cincinnati-based manufacturer Procter & Gamble Co. says its scientists also have found the asparagine connection. And Swiss and British scientists report in this week’s edition of the journal Nature that they, too, found the link.

It is the first clue to emerge in the mystery of acrylamide since Swedish scientists made the surprise announcement in the spring that high levels of the possible carcinogen are in numerous everyday foods: french fries, potato chips, some types of breakfast cereals and breads — plenty of high-carbohydrate foods that are fried or baked at high temperatures. The chemical was not found in boiled foods, which are cooked at lower temperatures.

Acrylamide is used to produce plastics and dyes and to purify drinking water. Although traces have been found in water, no one expected high levels to be in basic foods.

It causes cancer in test animals, but it has not been proved to do so in people. Still, Swedish scientists have said the levels are high enough that foodborne acrylamide might be responsible for several hundred cases of cancer in that country each year.

The food industry stresses that while fried potato products are getting most of the bad publicity — most testing so far shows the highest levels in them — acrylamide is in a wide variety of foods. Procter & Gamble said Friday that its testing found acrylamide in such previously unimplicated foods as roasted asparagus and banana chips.

Everyone should be eating a healthy whole food diet. By doing so you will limit the quantity of this and other potentially harmful substances. Remember fruits and veggies and whole grains will promote your health. Try to eat things as they occur in nature with the least amount of processing.

STUDY:

JOURNAL: Journal of the American Medical Association

AUTHORS: Christine Velicer

ABSTRACT: Women who use antibiotics to treat infections may be increasing their risk of breast cancer, a US study has suggested.

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COMMENTARY: Researchers found that women who used the drugs for up to 500 days were about 1.5 times as likely to develop cancer. Among higher users, the risk of death from the disease was nearly 3.5 times as great.

The association between disease and death was even stronger among those who used antibiotics for longer, although the authors of a report in the Journal of the American Medical Association stressed that more research was needed to establish whether the apparent association was causal or if other factors needed to be considered.

These included the possibility that immune systems were already undermined by conditions for which antibiotics were being taken or that inflammation of tissues linked to some conditions made them more suitable breeding grounds for tumours.

Scientists are already concerned about the excessive use of antibiotics to treat infections, blaming it for growing bacterial resistance to drugs.

The study, led by Christine Velicer of Washington University, Seattle, compared medical data for 2,266 women who had breast cancer with 7,953 women who did not.

In the report on their work, the researchers said: "While the implications for clinical practice will not be clear until additional studies are conducted, the results of this study support the continued need for prudent long-term use of antibiotics."

STUDY: Vitamin-rich foods, not supplements, appear best

JOURNAL: Journal of the American Medical Association

AUTHORS: Martha Clare Morris

ABSTRACT: In the latest work to show that vitamins may protect against dementia, new studies suggest that eating nuts, leafy green vegetables and other foods rich in antioxidants such as vitamin E may reduce the risk of Alzheimer’s.

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COMMENTARY: The connection, at least, is considered plausible: Antioxidant vitamins have been shown to block the effects of oxygen molecules called free radicals, which can damage cells and are thought to contribute to cancer and heart disease. And lesions typically associated with exposure to free radicals have been found in the brains of Alzheimer’s patients.

One of the studies found strong effects from vitamins E and C. In the other, results from vitamin E foods were more conclusive.

There was no protective effect in participants with a gene variation called apoplipoprotein E-4, which has been linked to the development of Alzheimer’s.

Other work has hinted that high levels of the amino acid known as homocysteine may also be associated with Alzheimer’s disease, suggesting that folic acid and other B vitamins may offer some protection.

There’s no question, experts say, that folic acid and B vitamins break down homocysteine in the body, thereby reducing blood levels. But the link between homocysteine and dementia still needs to be confirmed.

STUDY: Plant-based, edible compounds are one answer

JOURNAL: Diabetes Week

AUTHORS: Sam J. Bhathena

ABSTRACT: Obesity and diabetes mellitus are two nutritional disorders that have become major public health concerns in industrialized countries because of their epidemic proportions and association with major cardiovascular risk factors that are responsible for excess morbidity and mortality. Researchers are looking for ways to combat these diseases.

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COMMENTARY: Phytoestrogens are a group of biologically active plant-based compounds.

Phytoestrogens are present in edible plants that can be classified as isoflavones, lignans and coumestaus. Soybean is an abundant source of isoflavones in the human diet, while flaxseed is the richest source of lignans.

Earlier studies in obese animals and humans have suggested that soy, as a source of dietary protein, has significant antiobesity effects.

A study conducted in genetically obese mice found that soy protein and its hydrolsate were more effective than whey protein in weight reduction. This effect may be due to an active tetrapeptide present in soy. Several studies reported increased insulin sensitivity in rats fed isolated soy proteins compared with rats fed casein. A 37-kDa protein in soy appears to modulate insulin action on fat decomposition. Studies on the role of flaxseed and its components in obesity and diabetes in humans are limited.

Lean and obese rats were fed diets containing either 20% casein or 20% isolated soybean protein or 20% flaxseed meal for 26 weeks. The lean rats were hypertensive while the obese rats showed symptoms of type II diabetes. Obese rats had significantly higher levels of plasma glucose, triglycerides, total cholesterol, (high-density lipoprotein cholesterol [HDL-C] and low-density lipoprotein cholesterol [LDL-C]).

Soybean significantly decreased total cholesterol and LDL in both lean and obese rats but had no significant effect on glucose.

Flaxseed decreased total cholesterol and triglycerids in both lean and obese rats, but it significantly decreased HDL-C and LDL-C only in obese rats. Flaxseed also decreased glucose in lean but not in obese rats and it had greater effect on various parameters than did soybean.

Soybean and flaxseed affected plasma lipids and a number of enzymes. They also had varying effects on tissue weights in lean and obese rats. Obese rats compared with lean rats had significantly lower plasma creatinine but higher total bilirubin, blood urea nitrogen, alanine aminotransferase and lactate dehydrogenase.

Both soy and flaxseed meal decreased total bilirubin, protein and uric acid in the lean rats, but the effects in obese rats were mixed.

STUDY: Women with early-stage ovarian cancer may do better if they receive chemotherapy immediately after undergoing surgery.

JOURNAL: Journal of the National Cancer Institute 2003;95:94-95,113-132

AUTHORS: Dr. Mahesh Parmar

ABSTRACT: Two large, newly released European studies suggest that women with early-stage ovarian cancer may do better if they receive chemotherapy immediately after undergoing surgery.

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COMMENTARY: Both studies found chemotherapy reduced the risk of a cancer recurrence. One found the treatment increased survival, but the other did not.

However, the studies are not the final word on the benefits of chemotherapy following surgery, said Dr. Debbie Saslow, of the American Cancer Society, who was not involved in either study.

"Women still need to discuss their particular situations with their doctors and decide about which course of treatment may be best for them."

Currently, women diagnosed with early-stage ovarian cancer tend to have surgery and if the cancer comes back, additional surgery and chemotherapy are recommended, according to Saslow, director of breast and gynecologic cancer at the American Cancer Society. In about 50% of cases, women with early-stage cancer experience a relapse after surgery.

Previous studies have shown that some women with early-stage ovarian cancer can be cured by surgery alone and therefore can avoid the devastating side effects of chemotherapy.

One important factor is to determine how far the disease has progressed so an informed decision can be made, Slaslow explained.

In the first study, the International Collaborative Ovarian Neoplasm Collaborators led by Dr. Mahesh Parmar of the Medical Research Council Clinical Trials Unit in London, England looked at 477 women who either had chemotherapy after surgery or had surgery alone.

After five years, women who received chemotherapy had a 9% greater overall survival (79% versus 70%) and an 11% greater chance of not having a recurrence of their cancer (73% versus 62%), according to the report published in the January 15th issue of the Journal of the National Cancer Institute.

In the second study, 448 women with early-stage ovarian cancer had either chemotherapy and surgery or had surgery alone.

In this study, after 5.5 years no difference in overall survival was detected between the two groups of women. However, women who got chemotherapy were less likely to have their cancer come back, according to the study's lead author, Dr. J. Baptist Trimbos of Leiden University Medical Center in The Netherlands and colleagues.

Overall, 76% of patients treated with chemotherapy were recurrence-free compared with 68% of patients not treated with chemotherapy.

The trials included a mix of patients, some with a poor prognosis and others with a better prognosis, based on the types of tumors they had. The studies do not help determine which women can be spared chemotherapy.

More research needs to be conducted to better identify women "who do not require additional therapy, while also seeking to improve therapy in patients who do."