Red Meat Heme > Cancer

[Guest guest]

Med Hypotheses. 2007;68(3):562-4. Epub 2006 Oct 11.

Heme of consumed red meat can act as a catalyst of

oxidative damage

and could initiate colon, breast and prostate cancers,

heart disease

and other diseases.

Tappel A.

Department of Food Science and Technology, University

of California,

, CA 95616, USA. altappel@...

Dietary epidemiological studies indicate correlations

between the

consumption of red meat and/or processed meat and

cancer of the colon,

rectum, stomach, pancreas, bladder, endometrium and

ovaries, prostate,

breast and lung, heart disease, rheumatoid arthritis,

type 2 diabetes

and Alzheimer's disease. The correlation of all these

major diseases

with dietary red meat indicates the presence of

factors in red meat

that damage biological components. This hypothesis

will focus on the

biochemistry of heme compounds and their oxidative

processes. Raw red

meat contains high levels of oxymyoglobin and

deoxymyoglobin and

oxyhemoglobin and deoxyhemoglobin and cytochromes in

muscle and other

tissues. Cooked and processed meat contain hemichromes

and

hemochromes. After being eaten heme proteins are

hydrolyzed to amino

acids and peptides and the heme group which is

coordinated with strong

ligands. The iron of heme coordinates to the sulfur,

nitrogen or

oxygen of amino acids and peptides and other

biological components.

The coordinated heme groups are absorbed and

transported by the blood

to every organ and tissue. Free and coordinated heme

preferentially

catalyze oxidative reactions. Heme catalyzed

oxidations can damage

lipids, proteins, DNA and other nucleic acids and

various components

of biological systems. Heme catalysis with

hydroperoxide intermediates

can initiate further oxidations some of which would

result in

oxidative chain reactions. Biochemical and tissue free

radical damage

caused by heme catalyzed oxidations is similar to that

resulting from

ionizing radiation. Oxidative biochemical damage is

widespread in

diseases. It is apparent that decreasing the amount of

dietary red

meat will limit the level of oxidative catalysts in

the tissues of the

body. Increasing consumption of vegetables and fruits

elevates the

levels of antioxidative components, for example,

selenium, vitamin E,

vitamin C, lycopene, cysteine-glutathione and various

phytochemicals.

These detrimental processes of heme catalysis of

oxidative damage

hypothesized here are not well recognized. More

investigative studies

in this field need to be done.

[Guest guest]

Hi folks:

Checking PubMed for studies related to the one Jeff posted (below),

shows this one, which seems interesting:

Extracts from abstract:

" We examined the relationship between intakes of ...... meats,

vegetables, and fruits [and] levels of oxidative DNA damage ...... . "

" Intakes of raw and cooked vegetables were examined separately. Meat

intake was examined by type of meat (pork, beef, fish, chicken) and

by cooking temperature. "

" The model that best explained DNA damage ...... included the intake

of cooked vegetables and the sum of beef and pork intake. This model

accounted for 85% of the variation in DNA damage levels. "

" Preliminary results are suggestive of a positive association of DNA

damage with beef and pork intake and a negative association with

cooked vegetable intake. "

Eighty-five percent is a high number! The findings mentioned in the

abstract are not very surprising. But, while I haven't seen the full

text, the abstract implies that consumption of fruit, fish, chicken

and *raw* vegetables are neither positively nor negatively associated

with DNA damage - which IMO is REALLY interesting.

FULL ABSTRACT:

" Oxidative DNA damage levels in blood from women at high risk for

breast cancer are associated with dietary intakes of meats,

vegetables, and fruits. "

Djuric Z, Depper JB, Uhley V, D, Lababidi S, o S,

Heilbrun LK.

Barbara Ann Karmanos Cancer Institute, Wayne State University,

Detroit, Mich., USA.

OBJECTIVE: We examined the relationship between intakes of specific

foods--namely, meats, vegetables, and fruits--with levels of

oxidative DNA damage in women consuming their own usual diet or a

diet low in fat. DESIGN: Blood was obtained from women who had been

assigned randomly to a low-fat or nonintervention diet for 3 to 24

months. Levels of 5-hydroxymethyluracil, a type of oxidative DNA

damage, were determined. Diet data were obtained from 3-day food

records. SUBJECTS/SETTING: The 21 women were participating in an

outpatient clinic. All the women were healthy but had a first-degree

relative with breast cancer. INTERVENTION: The intervention was a

self-selected diet with a goal of 15% of energy from fat. MAIN

OUTCOME MEASURES: Existing data on oxidative DNA damage levels were

evaluated for possible relationships to foods eaten. Intakes of raw

and cooked vegetables were examined separately. Meat intake was

examined by type of meat (pork, beef, fish, chicken) and by cooking

temperature. STATISTICAL ANALYSES: Initial univariate analyses relied

on Spearman rank correlations of each food item with DNA damage.

Further analyses of the data were performed with univariate and

multivariate weighted least squares regression models. RESULTS: The

model that best explained DNA damage levels was a bivariate

regression model that included the intake of cooked vegetables and

the sum of beef and pork intake. This model accounted for 85% of the

variation in DNA damage levels among women. Preliminary results are

suggestive of a positive association of DNA damage with beef and pork

intake and a negative association with cooked vegetable intake.

APPLICATION: These observations, if confirmed in larger studies,

suggest specific dietary changes to reduce oxidative DNA damage

levels and possibly cancer risk. "

PMID: 9597024

Rodney.

--- In , Jeff Novick <chefjeff40@...>

wrote:

>

> Med Hypotheses. 2007;68(3):562-4. Epub 2006 Oct 11.

> Heme of consumed red meat can act as a catalyst of

> oxidative damage

> and could initiate colon, breast and prostate cancers,

> heart disease

> and other diseases.

> Tappel A.

> Department of Food Science and Technology, University

> of California,

> , CA 95616, USA. altappel@...

>

> Dietary epidemiological studies indicate correlations

> between the

> consumption of red meat and/or processed meat and

> cancer of the colon,

> rectum, stomach, pancreas, bladder, endometrium and

> ovaries, prostate,

> breast and lung, heart disease, rheumatoid arthritis,

> type 2 diabetes

> and Alzheimer's disease. The correlation of all these

> major diseases

> with dietary red meat indicates the presence of

> factors in red meat

> that damage biological components. This hypothesis

> will focus on the

> biochemistry of heme compounds and their oxidative

> processes. Raw red

> meat contains high levels of oxymyoglobin and

> deoxymyoglobin and

> oxyhemoglobin and deoxyhemoglobin and cytochromes in

> muscle and other

> tissues. Cooked and processed meat contain hemichromes

> and

> hemochromes. After being eaten heme proteins are

> hydrolyzed to amino

> acids and peptides and the heme group which is

> coordinated with strong

> ligands. The iron of heme coordinates to the sulfur,

> nitrogen or

> oxygen of amino acids and peptides and other

> biological components.

> The coordinated heme groups are absorbed and

> transported by the blood

> to every organ and tissue. Free and coordinated heme

> preferentially

> catalyze oxidative reactions. Heme catalyzed

> oxidations can damage

> lipids, proteins, DNA and other nucleic acids and

> various components

> of biological systems. Heme catalysis with

> hydroperoxide intermediates

> can initiate further oxidations some of which would

> result in

> oxidative chain reactions. Biochemical and tissue free

> radical damage

> caused by heme catalyzed oxidations is similar to that

> resulting from

> ionizing radiation. Oxidative biochemical damage is

> widespread in

> diseases. It is apparent that decreasing the amount of

> dietary red

> meat will limit the level of oxidative catalysts in

> the tissues of the

> body. Increasing consumption of vegetables and fruits

> elevates the

> levels of antioxidative components, for example,

> selenium, vitamin E,

> vitamin C, lycopene, cysteine-glutathione and various

> phytochemicals.

> These detrimental processes of heme catalysis of

> oxidative damage

> hypothesized here are not well recognized. More

> investigative studies

> in this field need to be done.

>