the ultimate guide to free radicals, antioxidants, and cancer · initiates free radicals in skin...

I N S I D E T H I S I S S U E

1. Getting Started

2. Where do free radicals come from?

3. Antioxidants To The Rescue

4. Antioxidant Supplements May Preserve and Prolong Your Life

5. Summary

The story of vitamin and mineral

supplementation begins with an understanding

of free radicals and antioxidants. It is widely

accepted in the scientific community that

substances known as free radicals cause cancer,

accelerated aging, and contribute to the

development and progression of heart disease

and stroke, Alzheimer’s disease and age-related

cognitive decline, cataracts and macular

degeneration of the eye, weakening of the

immune system, skin cancer, wrinkles and other

degenerative conditions. In fact, free radicals are

believed to play a role in more than sixty different

health conditions.

Getting Started By JAMES MESCHINO D.C., M.S., R.O.H.P

Global Integrative

Medicine Academy

The Ultimate Guide to Free

Radicals, Antioxidants,

and Cancer

So what are free radicals? A free radical is a molecule that possesses an unpaired

electron, which must attempt to become whole and stable by stripping an electron from

a neighboring molecule, as electrons spin around (orbit) the nucleus of an atom in pairs;

one spinning clock-wise and the other spinning counter-clock wise. Thus, an atom or

molecule with an unpaired electron will use what even means necessary to acquire the

missing electron to spin in the opposite direction around the nucleus, to pair itself up. If

an atom or molecule is missing an electron (free radical state) it will strip an electron

from a neighboring molecule, which was otherwise minding its own business. In turn, the

molecule that has had an electron stripped away is now converted into a free radical

and must now steal an electron from another nearby molecule, which in turn, converts

the nearby molecule into a free radical and so on. This chain reaction of free radical

propagation is known to cause damage to many cellular structures, including the cell

membrane, enzymes, the DNA (genetic blueprints) and the mitochondria (energy

factory) within the cell, to name a few important ones. Studies show that free radical

damage of this nature can cause alterations to the DNA of the cell that lead to cancer.

This is how cigarette smoking causes lung cancer, as cigarette smoke is loaded with free

radicals that attack the DNA of lung cells creating cancerous mutations. Free radical

damage to the cell also speeds up the aging process of the cell by damaging many of

the structures, internal regulatory mechanisms, and the energy-producing machinery of

the cell (mitochondria).

Where do free radicals come from?

Well, cigarette smoke, as I mentioned, is loaded with free radicals, including second-hand

smoke. This is why cigarette smoke has been shown to be responsible for approximately

30% of all human cancers. However, there are many other sources of free radicals. It may

surprise you to learn that some of the oxygen we breathe in gets transformed into free

radicals during the course of normal metabolism. These oxygen radicals cause damage

to body cells and tissues. If you have ever cut open an apple and left it exposed to the air

for a few minutes, you know that the exposed surface turns brown. This change in color is

caused by oxygen free radical attack. The same kind of reaction occurs in the body. Many

researchers have shown that this type of oxidizing over a lifetime produces much of the

aging of our tissues. In other words, to a certain degree we don’t age, we actually are

slowly rotting just like the apple. Fortunately we can slow down the rate of rotting (or

aging) by taking higher dose of antioxidants, as I will explain. However, the point is that

oxygen is a double-edged sword in that we need it to produce energy (without it we would

die in three minutes or so), but at the same time, approximately 5% of the oxygen present

in our cells gets converted into very aggressive free radicals (oxygen free radicals). In fact,

cancer expert, Dr. Bruce Ames, estimates that each cell in the body endures 10,000 free

radical hits per day just from oxygen free radicals. The cumulative effect of free radical

attack over our lifetime is responsible for a large degree of the aging process, the age-

related weakening of our immune system and the age-related increase in cancer

incidence and other degenerative diseases.

In addition to cigarette smoke and oxygen there are many other environmental and food-

borne free radicals that can enter the body, which can greatly increase free radical

damage to our bodies. Here are examples of some other dangerous, yet common, free

radicals:

1. Alcohol – alcohol generates many free radicals and is responsible for approximately

3% of all human cancers in North America

2. Heterocyclic amines – these are formed when you char meat on a Bar BQ or eat

blackened or Cajun-style proteins (meat or fish)

3. Polycyclic aromatic hydrocarbons (PAH) – these are formed when the fat in meat

drips on to the Bar BQ coals and smoke rises into the meat or fowl. The smoke

contains PAH, which then rises into the food on the grill. This is why smoked meat and

fish are known to contain high levels of PAH, and regular consumption of these foods

are associated with increased incidence of stomach and esophageal cancers.

4. Pesticides (e.g. DDT)

5. Nitrosamines – these are formed when you consume foods (often cold cuts) that

contain nitrate and nitrite salts. Once in the intestinal tract nitrates combine with

amines (derivatives of protein digestion) to form nitrosamines, which are associated

with cancer of the colon, rectum and other tissue sites.

6. Ultra-violet light (from the sun and tanning beds) – UV-light penetrates the skin

and converts oxygen within skin cells into free radicals by injecting them with an

unpaired electron from the photon energy in UV-light waves. These free radicals

then go on to cause skin accelerated skin aging and increase risk of skin cancer.

UV-light can also reach deep into the dermal layers and cause cross-linking of

collagen fibers, which results in skin wrinkling.

7. X-Rays – radiation beams fired through the body initiate free radical formation

in the our cells to a significant degree in much the same way that UV-light

initiates free radicals in skin cells.

8. Air Pollution – contains many free radicals of which nitrous oxide and polycyclic

aromatic hydrocarbons are important ones.

9. Occupational Free Radicals – these include substances such as carbon

tetrachloride, asbestos, vinyl chloride and heavy metals like mercury, cadmium

and lead.

As you can see, your body comes into contact with a great number of free radical

insults over your lifetime. Reducing your exposure to free radical as much is possible is

an important way to reduce disease risk and slow aging, but it is also vital to optimize

your antioxidant defenses, as antioxidants quench and neutralize free radicals and

thereby minimize free radical damage to your body.

The unique feature about antioxidants is that they quench, intercept and neutralize

free radicals, converting them into stable, non-harmful substances and thus,

prevent or halt free radical damage to your tissues. Antioxidants are able to

neutralize free radicals because they have the ability to donate an electron or

absorb an electron from a free radical molecule, without being converted into a free

radical themselves. Fortunately, the body makes several antioxidant enzymes such

as glutathione peroxidase, catalase and superoxide dismutase to help reduce free

radical damage to the body. Without these enzymes to protect us from the

damaging effects of oxygen free radicals alone, we would all be dead within hours.

The fact that our bodies synthesize these antioxidant enzymes is what enables us to

live in the earth’s atmosphere of 21% oxygen, and to use oxygen to power the energy

production pathways in our cells. However, the antioxidant enzymes that the body

makes require activation by certain minerals including manganese, magnesium,

zinc, copper and selenium that we get from food and supplements. As well, our

bodies require additional antioxidant protection from nutritional antioxidants such

as vitamin A, vitamin C, vitamin E, Beta-carotene, lycopene, lutein and zeazantin, and

bioflavonoids. Studies conducted over the past 25 years have provided evidence

that supplementing with many of these nutritional antioxidants, at levels beyond

what food alone can provide, can have a significant impact on preventing many

degenerative diseases, and slow the aging process. This is why many experts

strongly recommend that you take an antioxidant enriched, high potency, multi-

vitamin and mineral each day.

Antioxidants To The Rescue

In general, part of your life long wellness/anti-aging plan should include reducing your

exposure to unnecessary free radicals and maximizing your defenses against free

radical damage by consuming at least 5 servings per day of fruit and vegetables, and

by acquiring additional antioxidant protection from an antioxidant-enriched, high

potency, multi-vitamin and mineral supplement each day.

Antioxidant Supplements May Preserve and Prolong Your Life

In general, part of your life long wellness/anti-aging plan should include reducing your

exposure to unnecessary free radicals and maximizing your defenses against free

radical damage by consuming at least 5 servings per day of fruit and vegetables, and

by acquiring additional antioxidant protection from an antioxidant-enriched, high

potency, multi-vitamin and mineral supplement each day.

Antioxidants Reduce Cancer Risk Numerous studies indicate that higher intakes of various antioxidants from food and

supplements help to reduce risk of many human cancers. Several prospective studies

that began during the 1980’s, particularly ones done in Finland, and in Basel, Switzerland,

provided some of the first compelling evidence that people who have higher intakes of

vitamin C, vitamin E, and beta-carotene, and who maintain appreciable blood levels of

these nutrients through their lives, have a significantly lower risk of many cancers, than

do individuals with lower intake and/or blood levels. Antioxidants, like vitamin C, beta-

carotene, vitamin E and others, quench free radicals that can cause cancerous

mutations to the genetic material (DNA) of our cells.

Population studies show that the frequent ingestion of orange-yellow fruits and

vegetables, and dark green vegetables, which provide many antioxidant vitamins, is

associated with reduced cancer risk. As reported by Ziegler, a number of studies have

shown that a high total carotenoid intake (e.g. beta-cartoene, lycopene lutein etc.) is

associated with a significant reduction in risk of cancers of the lung, stomach, breast,

bladder and colon, as well as a several other tissue.

As reported by Gladys Block, approximately 90 epidemiological studies have

examined the role of vitamin C or vitamin C-rich foods in cancer prevention.

According to these findings, evidence is strong that vitamin C may protect against

cancers of the esophagus, oral cavity, stomach, and pancreas and is substantial for

cancers of the cervix, rectum, breast and lung. As for vitamin E, the association

between serum vitamin E levels and subsequent cancer risk has been examined in at

least 12 longitudinal studies. Overall, the studies showed, on average, a 3% lower blood

vitamin E levels among individuals who later developed cancer. In particular, vitamin E

appears to be protective against cancers of the stomach, pancreas, colon and

rectum, and with selenium may reduce risk of reproductive organ cancers in women

(e.g. breast cancer). Many of these preliminary studies were summarized in The

American Journal of Clinical Nutrition supplement to volume 54, in December, 1991.

Since these early reports many studies have been performed over the past 13 years

that have more closely examined the relationship between antioxidants and cancer

prevention.

A number of antioxidants, including vitamin C, vitamin E, and selenium have been

shown to be important in the prevention of colon cancer.

Colon Cancer

Selenium is a trace mineral that is known to prevent chemically-induced colon

cancer in many animal studies. In one study with rats that were fed a known cancer

causing chemical, the rats whose diets were supplemented with selenium had a

tumor yield of only 3%, whereas the rats who received no selenium supplementation

had a 29% tumor yield. Other animal studies have shown that selenium

supplementation can reduce the incidence of intestinal tumors by 50% compared

with rats given the cancer causing agent without selenium supplementation.

Human observation studies are equally as impressive. For example, areas in North

America with low soil and crop selenium concentrations, show higher rates for colon

and rectal cancers. Other human studies demonstrate that lower blood levels of

selenium are associated with an increased risk of developing colon cancer. In a study

of U.S. veterans, blood levels of selenium were measured in subjects with colorectal

cancer and those free from colon cancer. The results demonstrated that subjects with

blood selenium levels below 128 micrograms per liter were 4.2 times more likely to

have one or more cancerous polyps.

In a clinical trial using selenium to reduce risk of skin cancer 1,312 subjects were given

either 200 micrograms of selenium or a placebo for almost five years. The subjects

taking the selenium experienced a 58% reduction in colon and rectal cancers

compared with subjects taking the placebo pill.

More recently, a study by Dr. Mark Russo and associates at The University of North

Carolina (Chapel Hill) showed further supported for the role of selenium in the

prevention of colon and rectal cancers. In their study, patients who were referred for a

colonoscopy assessment, also had blood tests performed. As reported by these

authors, lower blood levels of selenium were associated with multiple cancerous

lessons in the colon. The average blood level for patients with cancerous lesions was

107 micrograms per liter compared to 120 micrograms per liter, for the cancer free

subjects.

The authors conclude that this data support a protective effect of selenium against

colon and rectal cancers after adjustments for possible confounding factors such as

smoking, alcohol intake, use of dandruff shampoo (which contains selenium), vitamin

E intake, vitamin C intake, iron intake, fat intake, and fiber intake. The researchers state,

"Our results demonstrate that individuals with high plasma (blood) selenium levels are

at a decreased risk for colorectal adenomas (cancerous lesions)". An increase of 30

micrograms per liter in blood selenium level was associated with a 50% reduction in

risk of colon cancer lesions.

It is important to note, that other human studies by Dr. Willett, and Dr. Solonen , also

reported, a 2 and 3 fold increased risk for colon and intestinal cancer respectively, in

patients presenting with low blood selenium levels when compared to patients with

higher blood levels.

There are several ways that selenium is thought to reduce cancer risk. Selenium may

act as an antioxidant by increasing activity and levels of a powerful antioxidant

enzyme called glutathione peroxidase.

Glutathione peroxidase is considered a strong anticancer agent within the body.

Selenium supplementation also decreases the formation of the cancer permissive

prostaglandin hormone known as prostaglandin series-2, which I will discuss in more

detail in the next section. Selenium metabolism itself may initiate changes that lead to

programmed-cell death of cancer cells and pre-cancerous cells. Selenium is an

essential nutrient for humans; it fulfills the physiological requirements for more than 13

human enzymes and proteins.

The average intake of selenium from food sources is shown to be between about 50

micrograms daily. Is it adequate? This is not sufficiently adequate to maximize out

cancer defenses according to the available research. The truth is that selenium

consumed as a dietary supplement, beyond levels attainable from food, at 100-200

micrograms (mcg) per day, has been shown to reduce the incidence of lung, colorectal

and prostate cancer in humans.

As reported by B Combs and fellow researchers, selenium blood levels of approximately

120 ng/ml (1.5 umol/ml) may be optimal for cancer prevention in general. The most

recent estimates suggest that women require a minimum of 96 micrograms per day

and men require at least 120 micrograms per day to support plasma levels at 120 ug/ml

(micrograms per milliliter). As for safety, toxicity of selenium begins at doses starting at

1,000 micrograms per day, so 100-200 mcgs of selenium supplementation from multiple

vitamin is extremely safe.

Vitamin E has also been shown to reduce risk of colon cancer. On July 16, 1997, W.L.Stone

and A.M.Papas reviewed the world-wide scientific evidence related to vitamin E in the

prevention of colon cancer (Journal of the National Cancer Institute).

Previous studies dating back to 1982 demonstrated that 400 mg of vitamin E and 400

mg of vitamin C, when taken daily, were able to dramatically reduce the formation of

cancer-causing agents (fecal mutagens) in the colon of test subjects.

Like selenium, Vitamin E also inhibits the formation of a dangerous prostaglandin

hormone known as Prostaglandin E2. High levels of Prostaglandin E2 are linked to

increased risk of colon cancer because it encourages the rapid division and growth of

tumor cells and it helps cancer cells escape surveillance by the body's immune system

that would otherwise kill these cancer cells in the normal course of events. By

suppressing the formation of Prostaglandin E2, vitamin E helps prevent tumor cells from

growing and spreading and enables the immune system to function more effectively to

identify and destroy cancer cell that may emerge.

All of the animal studies reviewed by Dr. Prasad and fellow researchers, suggest

strongly that colon cancer is reduced when animals are supplemented with vitamin E,

after being exposed to known cancer-causing agents.

Animal and human studies are highly suggestive that vitamin E and selenium work

synergistically to reduce risk of colon cancer.

More recently, the Iowa Women's Health Study demonstrated a very strong protective

effect for vitamin E in the prevention of colon cancer. The Iowa Women's Health Study

was a large-scale study of 35,000 women between 55 and 66 years of age who had no

previous history of cancer.

This 4-year study provided convincing data that a high intake of vitamin E was

associated with a reduced risk of colon cancer. Women in the top 20% level of vitamin E

intake had a 66% lower risk of developing colon cancer than women ingesting vitamin E

in the lowest 20% intake range.

In almost all cases, the women with a high intake of vitamin E were taking supplements

containing Vitamin E.

Results from the Alpha-Tocopherol, Beta-Carotene, Cancer Prevention Study of 29,000

male smokers from Finland also indicated that a daily supplement of 50 mg of vitamin

E helped to prevent the subsequent development of colon and rectal cancer.

From a practical standpoint, I recommend that adults ingest 400 I.U. of vitamin E per

day, from a high potency multi-vitamin and mineral, as a means to help prevent

colon cancer, and other cancers. In fact, Vitamin E plays a role in the prevention

of many degenerative diseases, as I will outline in this section. Vitamin E is fat-

soluble, so you must take it with a meal that provides some fat in order for it to be

absorbed from your intestinal tract into the blood stream. The same is true for

Vitamin A, beta-carotene, lycopene, lutein, (other carotenoids) Vitamin D and

Vitamin K.

Vitamin C, in a number of different types of studies, has consistently been shown to be

associated with a reduced risk of colon cancer. Vitamin C acts as an antioxidant in the

intestinal tract and when supplemented, has been shown to decrease the

concentrations of cancer-causing chemicals in fecal matter. Vitamin C also blocks the

formation of cancer-causing nitrosamines within the entire intestinal tract. Vitamin C

supplementation was also shown to reduce the recurrence of colon polyps by 35%

compared to only 23% in the placebo group, in a 2.5- year study of polyp sufferers.

Prostate Cancer

One of the proposed mechanisms for the development of prostate cancer involves

free radicals, as a number of studies suggest a link between free radicals (oxidative

stress) and tumor development within the prostate

In several studies higher intakes and/or blood levels of the antioxidants vitamin E,

selenium and lycopene have been associated with decreased prostate cancer

incidence.

In the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study, long-term

supplementation with vitamin E was associated with a 32% decrease in the incidence

of prostate cancer compared with those not receiving vitamin E supplementation.

Moreover, death from prostate cancer was 41% lower among men receiving the

vitamin E supplement. The length of this supplementation study was 5-8 years and the

dosage of vitamin E was 50 mg (alpha-tocopherol).

Previous studies have observed that low blood levels of vitamin E in smokers are

associated with an increased risk of prostate cancer.

Many researchers believe that antioxidant function is an important means to prevent

prostate cancer initiation and promotion. This contention is further supported by the

work of Clark and fellow researchers, who demonstrated that supplementation with

the mineral selenium (mean time period 4.5 years) was associated with a 63% lower

incidence of prostate cancer. Blood levels of selenium have been reported to be low in

patients with prostate cancer. In preliminary reports, people with the lowest blood

levels of selenium had between 3.8 and 5.8 times the risk of dying from prostate cancer

compared with those who had the highest selenium levels.

The Health Professionals Follow-up Study also supports the hypothesis that antioxidant

function can prevent prostate cancer. In this study of nearly 48,000 subjects E.

Giovannucci and fellow researchers reported that a significant decrease in risk of

developing prostate cancer was associated with higher intake of lycopene.

It is interesting to note that the highest concentrations of lycopene occur in the testes,

adrenals, and prostate gland. It is estimated that a minimum 4-6mg daily intake of

lycopene is needed for prostate protection. An intake level of at least 6 mg per day or

more of lycopene was associated with approximately a 21% reduction in prostate

cancer incidence in The Health Professionals Follow-up Study, compared with men

consuming less than 2.3 mg per day.

Lycopene is the most effective quencher of singlet oxygen (a very aggressive and

harmful oxygen free radical) of the major carotenoids (beta-carotene-like

compounds) and is the primary carotenoid in the blood and various tissues, including

the prostate gland.

Taken together, the emerging research suggests that vitamin E, selenium and

lycopene supplementation, at specific dosages, may significantly reduce the risk of

prostate cancer.

Prostate cancer is the most common cancer in males in North America.

Other nutritional factors and supplements may also help to prevent prostate cancer

and are discussed in more detail in the prostate health section of the fellowship

program.

Scientific investigation has revealed that vitamin E inhibits the growth of certain

malignant cells, including certain human prostate and breast cancer cell lines.

In human populations, several epidemiologic (observational) and clinical intervention

studies have suggested that vitamin E supplementation can inhibit the development

of certain cancers. In particular, the studies by Knekt, Malvy and the Alpha-Tocopheral,

Beta-Carotene Cancer Prevention Study Group have all provided evidence that

vitamin E supplementation is associated with reduced risk of certain cancers, including

breast cancer. For example, in the Nurses’ Health Study there was a 16% decreased risk

of breast cancer in women within the top 20% of vitamin E intake compared to those in

the lowest 20% range. Women in the top 20% intake range were taking vitamin E

supplements in some form, to a large degree.

Vitamin E supplementation is also associated with reducing the spread and

progression of breast cancer in women who have already had the disease. According

to the study by A. Fleischauer and fellow researchers, vitamin E supplementation in

breast cancer survivors is associated with 25-35% decrease in recurrence and

mortality compared to non-users of vitamin E supplements. In fact, in women who

have had breast cancer, a cocktail of various antioxidants was shown to be helpful in

the study by K. Lockwood and fellow researchers.

Breast Cancer

These researchers conducted an 18-month study, involving 32 women with breast

cancer. These women were put on a nutritional protocol consisting of high dose

antioxidants and accessory nutrients. The women were between 32 and 81 years of

age and classified “high risk” because of tumor spread to the lymph nodes in the axilla

(under the arm). The nutritional protocol, which was added to the normal surgical and

therapeutic treatments for breast cancer, consisted of a combination of the following

antioxidants. Vitamin C, 2,850 mg; vitamin E, 2500 IU; beta-carotene, 32.5 IU selenium,

387mcg, plus secondary vitamins and minerals, essential fatty acids (1.2 gm gamma

linolenic acid and 3.5 gm omega-3 fatty acids) and coenzyme Q10, (90-390 mg per

day). Biochemical markers, clinical condition, tumor spread, quality of life parameters,

and survival were followed during the 18-month trial. Compliance was excellent. The

main observations were: none of the patients died during the study period (the

expected number was four); none of the patients showed signs of further distant

metastases; quality of life was improved (no weight loss, reduced use of painkillers);

and six patients showed apparent partial remission.

This study indicates that various antioxidants and other nutrients can work

synergistically to help contain and prevent cancer to some degree.

Antioxidants, such as vitamin E, beta-carotene and other carotenoids have been shown to protect against cervical cancer in certain studies. In several, but not all studies, elevated blood levels of folic acid, beta-carotene, lycopene, and vitamin E have been found to protect against cervical dysplasia (a precancerous condition of the cervix) In a recent study of 32 black women, by P. Kanetsky and fellow researchers, women with higher intake and blood levels of lycopene were one-third as likely to have cervical dysplasia as were women with the lowest one-third of lycopene blood levels. In addition, they were one-fourth as likely to develop the dysplasia if they had higher intake and blood levels of vitamin A, than were women with the lowest one-third of vitamin A blood levels. Vitamin A is also an antioxidant vitamin and has other anti-cancer properties.

Smoking is a known risk factor for the development of cervical dysplasia and beta-carotene has been shown to be effective against smoking-related cervical dysplasia and cervical cancer. This was documented in studies by HC de Vet and fellow researchers, and W Jr. Winkelstein.

In general, evidence suggests that low vitamin status of these antioxidants, folic acid (a B-vitamin), cigarette smoking and human papillomavirus infection combine to contribute to the risk and progression of cervical dysplasia.

Cervical Cancer

In a study of patients with mild or moderate cervical dysplasia, 30 patients were

treated with 30mg (50,000 I.U.) of beta-carotene orally for up to six months. More than

70 percent of patients showed reversal of their condition by six months. However, only

three months were required to realize optimal reversal of this condition, according to

biopsy studies of shed cervical cells.

At this time there is sufficient evidence to suggest that nutrition and antioxidant

supplementation play a vital role in the prevention of cervical dysplasia and, in some

cases, can reverse this condition in its early and moderate stages.

Stomach Cancer

Stomach cancer and colon cancer have been shown to susceptible to the influence of

a carcinogen known as nitrosamines. Nitrosamines represent an important group of

environmental carcinogens. On average, individuals consume approximately 74 mg

per day of nitrates in North America. Processed meats that are treated are preserved

with nitrate and nitrite salts are a major source of these carcinogens. Many alcoholic

beverages contain nitrates, and soils treated with nitrogen fertilizers give rise to many

plant foods that now contain more nitrates than was the case before the use of

nitrogen fertilizers.

Thus, all of us are exposed to some background levels of nitrates entering the body.

Within the stomach and intestinal tract nitrates can combine with protein (amino

acids) to form cancer-causing nitrosamines. Both vitamin C and vitamin E have been

shown to block the formation of nitrosamines when taken as supplements with, or

shortly after, a meal containing nitrates and protein. For optimal protection, taking 500

mg of vitamin C, twice per day has been shown to block as much as 85-100% of

nitrosamines formation under conditions of a high nitrate intake. A number of different

types of studies have consistently shown a strong protective effect of vitamin C

against stomach and colon cancer. The same is true regarding vitamin E. For vitamin E,

a daily dosage of 400 IU can help block the formation of nitrosamines.

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