Drawing Health from Vitamin E
Dietary oils and fats have long been recognised as a macronutrient with a primary function to provide a concentrated source of energy for human metabolic processes.
While being cautious of over-consuming fats, we should recognise that these account for more than twice the energy density (9 calories/g) of proteins or carbohydrates (4 calories/g).
Apart from making foods palatable, fats are required for the carriage of the fat-soluble Vitamins A, D, E and K in our body.
Triglycerides, which are basically fatty acids bound to a glycerol molecule, make up 96-99% of the dietary fats consumed. The remainder, termed 'unsaponifiable matter', includes fat-soluble minor components that serve a functional purpose in the oil or fat.
In crude edible oils these components are divided two groups. The first comprises non-nutritional, largely pro-oxidant odiferous components and free fatty acids that must be removed through refining to produce the typically bland golden oil preferred by consumers.
The second group consists of the important and nutritionally functional group, which includes tocopherols and tocotrienols (collectively termed Vitamin E), carotenes (pro-Vitamin A components), phytosterols, squalene and co-enzyme Q.
Refining crude oils either reduces the content of these components or removes them, as in the case of carotenes. However, the use of technology has helped recover Vitamin E, carotenes and phytosterols from waste products of the edible oil industry.
Role of Vitamin E
Vitamin E functions as a chain-breaking antioxidant and prevents the accumulation of lipid peroxidation products. Daily dietary sources appear adequate to avoid any deficiency syndromes, which are rarely seen in any case.
However, consumption of Vitamin E in larger doses than that available from our diet has been recommended to prevent the onset and progression of degenerative diseases including cancer and cardiovascular disease.
In nature, Vitamin E occurs in eight isomeric forms, the four tocopherol and four tocotrienol isomers (see table). Of these, alpha-tocopherol is the most abundant.
Most natural Vitamin E preparations bought over the counter are of this isomeric form, mainly extracted from the refining scum (waste) of soybean oil refining. If the source is corn oil, substantial amounts of beta-tocopherol are also present.
Tocotrienols are a curiosity of nature and occur in - appreciable quantities in only palm oil and rice bran oil. Wheat germ and barley germ oils are less important sources.
Tocotrienols differ structurally from tocopherols and this appears to influence the physiological effects.
Over the past three decades Vitamin E has been looked upon as an important health-giving minor nutrient that protects against degenerative diseases.
The hypothesis is that oxidised low-density lipoprotein enhances cardiovascular disease (CVD), and the belief that Vitamin E potentially protects against oxidation is gaining credence.
Vitamin E does inhibit oxidation processes and protect against atherosclerosis. However, the evidence from large-scale population (epidemiological) studies is conflicting.
Only one of four studies demonstrated that Vitamin E protects against CVD. Therefore, there is insufficient evidence to recommend the consumption of Vitamin E as a dietary supplement to prevent heart disease in general populations.
In the case of diabetes, the data strongly suggested increased oxidative stress and that the Vitamin E may have a role as a chain-breaking antioxidant. The overall evidence for cancer prevention is weaker than that for protection against CVD.
Understanding of the effects of tocotrienols is just emerging, based on their recent availability from palm oil and rice bran oil processing. The primary advantage of tocotrienols is that they are natural food components with no adverse effects.
They have far superior chain-breaking antioxidants than tocopherols. They lower blood cholesterol through a mechanism akin to the family of 'statin' drugs used to control high blood cholesterol levels. Tocotrienols regulate a key liver enzyme that is involved in the synthesis of cholesterol.
In a controlled human clinical trial, patients suffering from carotid arterial stenosis who were given palm tocotrienol supplements showed several degrees of improvement, compared to those receiving Vitamin E (alpha-tocopherol) supplements.
Atherosclerosis is often mediated by oxidative damage of low-density lipoproteins. Tocotrienols showed greater protection in this area than tocopherols, based on evidence from several animal studies.
Interesting developments have been recorded for tocotrienols in cancer studies. In human breast cancer cell culture studies, palm tocotrienols appear to inhibit the growth of cancer cells. These perform even more effectively in combination with the drug tomaxifen, used to treat breast cancer.
Asian 'mega trend' on health foods
Consumer behaviour across Asia is changing to reveal the face of health conscious shoppers.
A recent survey of about 40,000 households in various countries has shown that, year on year spending on health foods has grown significantly to become the 'Number One mega trend'.
The Taiwanese led the pack, allocating 50% of their household spending for purchase of such products as fruit and vegetables, RTD tea, vitamins, cereals, yoghurt products and liquid milk.
About 90 per cent of households in Vietnam - more than in any other country surveyed - expressed a willingness to pay more for health foods and drinks.
Asia also fared better than the West in the comparison of those overweight or obese, although this position may be negated by increased spending on snack foods in countries like Vietnam, Malaysia and Thailand.
Quick detector of deadly bacteria
US scientists at the Department of Agriculture have developed a `flow cytometer' that can handle up to 100 samples at a time in detecting bacteria and obtain more precise . results as well.
Listeria monocytogenes and Candida albicans bacteria can be identified with accuracy within a day, compared to about three days previously.
Listeria is a hardy pathogen that resists freezing, drying and heat processes and has been responsible for numerous and sometimes fatal outbreaks of food poisoning. The yeast Candida can be lethal to people with weakened immune systems.
The machine uses molecules called `probes' to find and bind corresponding pieces of species-specific DNA. A fluorescent marker tells the cytometer which DNA sequence was detected, with the identity of the species displayed as colour-coded bar graphs.
The test can be used to check for yeasts that cause food and beverage spoilage. It could also speed up the search for yeasts adept at fermenting cornstarch into ethanol or those used for the control of fruit-storage rots.
Foods typically associated with Listeria monocytogenes contamination include ready-to-eat products made with red meat, poultry meat and fish, including frankfurters, pdte, smoked salmon and fermented raw meat sausages.
It could also affect dairy products like soft cheeses, such as brie, camembert and roulade, semi-soft farmhouse cheeses and unpasteurised milk. Prepared salads, such as coleslaw, also support the growth of the pathogen.
The innovation could therefore prove especially useful in hazard analysis and critical control point programmes at food-processing plants.
Gynaecological Cancers - Are You at Risk?
A risk factor is anything that raises a person's chance of getting a disease. You can control some of them, but not all of them.
Risk factors for gynaecological cancers include:
- Lifestyle choice e.g. diet.
- Environment e.g. passive smoking.
- Genetic make-up or family history.
- Another disease or medical problem.
These things mix together with different effects on different people.
Some people are more sensitive to risk factors than others. Just because you have one or even several risk factors does not mean you will definitely get cancer.
Here are some questions to assess your risk:
1. Are you above 40 years o f age?
The risk of cervical, ovarian and uterine cancer increases with age.
Most of the cancers occur in the older age group.
You have a higher risk of uterine cancer if you are obese. Being overweight raises the amount of oestrogen a woman is exposed to throughout her life.
Oestrogen is a female reproductive hormone mainly released during the menstrual cycle. High levels of oestrogen may cause cells in the uterus to become cancerous.
3. Do you smoke?
Smoking increases your risk of cervical cancer. Cigarette smoke contains chemicals that damage the genetic structure (DNA) of the body's cells. DNA damage causes cells to become cancerous.
But after a person stops smoking, new cells replace damaged ones.
4. Are you diagnosed with any form of cancer?
- You are at a higher risk of ovarian cancer if you also have breast and/or colon cancer.
- You are at a higher risk of uterine cancer if you are on medication for breast cancer.
5. Do you have a family history of cancer?
If someone else in your family has uterine or ovarian cancer, you are at a higher risk of either.
This is because a small number of uterine and ovarian cancers are linked to mutations in the genetic structure (DNA) of the body's cells. These mutations can be passed on from generation to generation.
6. Are you a diabetic?
Diabetics are at a higher risk of uterine cancer. The reason is unclear but it may be that diabetes raises the level of oestrogen in a woman's body and high levels of oestrogen may cause cells in the uterus to become cancerous.
7. Did you have your periods before 12 years of age?
Having periods before the age of 12 increases your risk of uterine cancer.
8. Did you have a late menopause (after 55 years)?
You have a higher risk of uterine cancer if you menopause late. If you have periods early and go through menopause (when regular periods stop) at a late age, it exposes you to more menstrual cycles, which in turn exposes you to high levels of oestrogens.
9. Were you ever on fertility medicine?
If you have taken fertility pills and are still childless, you are at a higher risk of ovarian cancer.
It appears that fertility pills like clomiphene result in constant uninterrupted ovulation which used for more than 12 months, may lead to an increased risk of ovarian cancer.
10. Did you have sexual intercourse before the age of 16?
Women who have sex for the first time at an early age have a higher risk of cervical cancer. Scientists are not sure why.
One reason may be that the human papillomavirus (HPV) more easily infects a young woman's cervix.
HPV is a sexually transmitted disease. Some types of HPV can cause cells in the cervix to become cancerous.
11. Did you have more than 2 sexual partners?
Women who have multiple sexual partners tend to have a higher risk of cervical cancer. More partners mean more chances of getting HPV (see above).
Women who have more partners also have a higher risk of STDs and pelvic infection.
12. Have you ever had any form of STDs (sexually transmitted diseases)?
A history of STDs puts you at a higher risk of cervical cancer. STDs include chlamydia, gonorrhea, herpes and HPV, some of these may cause cells in the cervix to become cancerous.
If you think you have STD, talk to a doctor immediately. STDs may be hard for you to talk about but it is important to get treated. Most STDs are treatable if found early.
13. Are you taking hormone replacement therapy?
Taking oestrogen without progestorone puts you at an increased risk of uterine cancer.
Hormone therapy refers to medications that help ease the symptoms of menopause like hot flushes and vaginal dryness. It contains hormones that are similar to the female reproductive hormones, oestrogen and progesterone, which the body stops making in large quantities after menopause.
Women who take post-menopausal hormones containing oestrogen only for 10 or more years have a higher risk of uterine cancer as high levels of oestrogen after menopause may cause the cells in the uterus to become cancerous.
Are You Protected?
The following are protective against gynaecological cancers. Try to achieve as many as possible to lower your cancer risk!
It is important to keep in mind that avoiding risk factors does not guarantee that you will not get cancer. Also, most people with a particular risk factor for cancer do not actually get the disease. Talk to your doctor about the methods of preventing cancer that might be effective for you.
1. Have you ever used contraceptive pills for more than 5 years?
If you have taken birth control pills for at least 5 years, you have a lower risk of uterine and ovarian cancers.
The longer you take the pill, the more you lower your risk. Birth control pills keep the woman from ovulating (when the ovaries produce an egg). It has been suggested that constant ovulation causes damage to the ovaries and predisposes to ovarian cancer.
2. Do you use condoms?
The use of condoms or diaphragms lowers the risk of cervical cancer.
These methods of birth control act as a barrier against HPV, which is a sexually transmitted disease and can cause the cells in the cervix to become cancerous.
3. Have you given birth to more than one child?
If you have never given birth or have only one child, you are at a higher risk of ovarian and uterine cancers.
The fewer pregnancies a woman has, the more she ovulates. Ovulating raises the amount of oestrogen a woman is exposed to throughout her life.
Never being pregnant thus raises the level of oestrogen and lowers the level of progesterone in a woman's body and this combination may cause the cells in the womb to become cancerous.
4. Have you ever breastfed your children?
Breastfeeding for at least one year combined lowers your risk of ovarian cancer. The more a woman breastfeeds, the less she ovulates.
5. Are you ligated (sterilized)?
If you had your fallopian tubes tied, you have a lower risk of ovarian cancer. After the operation there may be changes in hormone levels which help protect the ovaries from cancer.
6. Have you had your uterus (womb) removed?
Women who have had a hysterectomy have a lower risk of ovarian cancer.
7. Do you go for regular PAP smears?
Women who get a PAP smear regularly have a lower risk of cervical cancer. The test detects cells in the cervix that may turn into cancer. If these cells are found early, a woman can be treated before cervical cancer develops.
Source : KK Gynaecological Cancer Centre (KKGCC), K.K. Hospital, Singapore.
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