All posts in Knowledge

Ancient Egyptians were Vegetarian

Print pagePDF pageEmail page

(Inside Science) — Did the ancient Egyptians eat like us? If you’re a vegetarian, tucking in along the Nile thousands of years ago would have felt just like home.

In fact, eating lots of meat is a recent phenomenon. In ancient cultures vegetarianism was much more common, except in nomadic populations. Most sedentary populations ate fruit and vegetables.

Although previous sources found the ancient Egyptians to be pretty much vegetarians, until this new research it wasn’t possible to find out the relative amounts of the different foods they ate. Was their daily bread really daily? Did they binge on eggplants and garlic? Why didn’t someone spear a fish?

A French research team figured out that by looking at the carbon atoms in mummies that had lived in Egypt between 3500 B.C. and 600 A.D. you could find out what they ate.

 

More

Tomatoes are likely to reduce depression

Tomatoes are likely to reduce depression
Print pagePDF pageEmail page

In a new study, researchers found that those who eat tomatoes two to six times a week were 46 per cent less likely to suffer the blues than those eating them less than once a week.

Eating them every day slashed the risk by 52 per cent, according to the study.

But other fruits and vegetables do not have the same benefits. Eating healthy foods like cabbage, carrots, onions and pumpkins appeared to have little or no effect on psychological well-being, the study found.

Tomatoes are good source of lycopene, an antioxidant that gives them their deep red colour and has been linked with reducing the risk of prostate cancer and heart attacks.

The team of researchers from China and Japan, led by Dr Kaijun Niu from China’s Tianjin Medical University, wanted to investigate preliminary reports that lycopene might also promote psychological and well as physical health by reducing oxidative stress, or damage to healthy brain cells.

They analysed the mental health records and dietary habits of just under 1,000 elderly Japanese men and women aged 70 or over.

The researchers said they cannot be sure if lycopene in tomatoes directly affects the mind, or whether it simply protects against the depression caused when people develop potentially fatal diseases like cancer.

“These results suggest that a tomato-rich diet may have a beneficial effect on the prevention of depressive symptoms. In contrast, no relationship was observed with intake of other kinds of vegetables,” the Daily Mail quoted the researchers as writing in a report on the findings published in the Journal of Affective Disorders.

More

Increased B vitamins may ease PMS

Print pagePDF pageEmail page

Higher intakes of the B vitamins thiamine and riboflavin from the diet may reduce the incidence of premenstrual syndrome (PMS) by about 35 percent, suggest new findings. According to a new paper published in the American Journal of Clinical Nutrition, the link between B vitamins and PMS is biologically plausible since B vitamins such as thiamine and riboflavin are known to play important roles in the synthesis of various neurotransmitters involved in PMS.

While most women experience mild emotional or physical premenstrual symptoms, as many as 8-20 per cent of women experience symptoms severe enough to meet the definition of premenstrual syndrome, which can substantially interfere with daily activities and relationships. The new study, performed by researchers from the University of Massachusetts, Harvard, and the University of Iowa, indicates that increase intakes of certain B vitamins from food sources may help reduce the incidence of PMS.

Using data from 1,057 women with PMS and 1,968 women without PMS participating in the Nurses' Health Study II cohort, the researchers found that women with the highest average intakes of riboflavin two to four years prior to diagnosis were associated with a 35 percent lower incidence of PMS than women with the lowest average intakes. On the other hand, the researchers did not observe any benefits with other B vitamins, including niacin, folate, B6, and B12. In addition, supplemental intakes of these vitamins was not linked to PMS incidence, they added. “We observed a significantly lower risk of PMS in women with high intakes of thiamine and riboflavin from food sources only,” wrote the researchers. “Further research is needed to evaluate the effects of B vitamins in the development of premenstrual syndrome.”

Beyond the B vitamins, there is also some evidence for the potential of a diet rich in calcium and vitamin D to lower the risk of developing PMS, a condition that affects up to a fifth of all women. According to a study published in 2005 in the Archives of Internal Medicine (Vol. 165, pp1246-1252), researchers from the University of Massachusetts and GlaxoSmithKline reported for the first time that calcium and vitamin D may help prevent the initial development of PMS.

Source: The American Journal of Clinical Nutrition. Published online ahead of print, doi: 10.3945/ajcn.110.009530 “Dietary B vitamin intake and incident premenstrual syndrome” Authors: P.O. Chocano-Bedoya, J.E. Manson, S.E. Hankinson, W.C. Willett, S.R. Johnson, L. Chasan-Taber, A.G. Ronnenberg, C. Bigelow, E.R. Bertone-Johnson

More

Pecans Can Prevent Heart Disease

Print pagePDF pageEmail page

A new research study from Loma Linda University (LLU) demonstrates that naturally occurring antioxidants in pecans may help contribute to heart health and disease prevention; the results were published in the January 2011 issue of The Journal of Nutrition.

Pecans contain different forms of the antioxidant vitamin E — known as tocopherols, plus numerous phenolic substances, many of them with antioxidant abilities. The nuts are especially rich in one form of vitamin E called gamma-tocopherols. The findings illustrate that after eating pecans, gamma-tocopherol levels in the body doubled and unhealthy oxidation of LDL (bad) cholesterol in the blood decreased by as much as 33 percent. Oxidized LDLs may further contribute to inflammation in the arteries and place people at greater risk of cardiovascular problems. “Our tests show that eating pecans increases the amount of healthy antioxidants in the body,” says LLU researcher Ella Haddad, DrPH, associate professor in the School of Public Health department of nutrition. “This protective effect is important in helping to prevent development of various diseases such as cancer and heart disease.”

These findings are from a research project designed to further evaluate the health benefits of pecans, according to Dr. Haddad. She analyzed biomarkers in blood and urine samples from study participants (a total of 16 men and women between the ages 23 and 44) who ate a sequence of three diets composed of whole pecans, pecans blended with water, or a control meal of equivalent nutrient composition. The pecan meals contained about three ounces of the nut. Samples were taken prior to meals and at intervals up to 24 hours after eating. Following the test meals composed of whole pecans and blended pecans, researchers found that amounts of gamma-tocopherols (vitamin E) in the body doubled eight hours after both meals, and oxygen radical absorbance capabilities (ORAC — a scientific method for measuring antioxidant power in the blood) increased 12 and 10 percent respectively two hours after the meals. In addition, following the whole-pecan meal, oxidized LDL cholesterol decreased by 30 percent (after 2 hours), 33 percent (after 3 hours), and 26 percent (after 8 hours).

“This study is another piece of evidence that pecans are a healthy food,” says Dr. Haddad. “Previous research has shown that pecans contain antioxidant factors. Our study shows these antioxidants are indeed absorbed in the body and provide a protective effect against diseases.” Research from Loma Linda University published earlier in the Journal of Nutrition showed that a pecan-enriched diet lowered levels of LDL cholesterol by 16.5 percent — more than twice the American Heart Association’s Step I diet, which was used as the control diet in that study. Similarly, the pecan-enriched diet lowered total cholesterol levels by 11.3 percent (also twice as much as the Step I diet).

More

High fibre diet helps you live longer

Print pagePDF pageEmail page

Eating a diet rich in fibre has long been known to help keep your digestive tract working properly. It’s also thought to lower the risk of heart disease, some cancers and diabetes. Now, a new study suggests it could reduce the risk of death from cardiovascular, infectious and respiratory diseases. People who ate a high-fibre diet decreased their risk of dying over a nine year period compared to those who ate less fibre, according to a new study in the Archives of Internal Medicine.

The findings are based on a diet study from the National Institutes of Health and AARP, which included 219,123 men and 168,999 women ages 50 to 71 when the study began. Researchers from the National Cancer Institute examined food surveys completed by the participants in 1995 or 1996. After nine years about 11,000 people died and researchers used national records to determine the cause.

People who ate at least 26 grams per day were 22 percent less likely to die than those who consumed the least amount of fibre — about 13 grams per day or less. Men and women who consumed diets higher in fibre also had a reduced risk of cardiovascular, infectious and respiratory diseases, the study found. Getting fibre from grains seemed to have the biggest impact, the authors write.

The study has some limitations — mainly, people who ate high-fibre diets might also have been more likely to eat healthier diets overall, attributing to their longevity. Still, the study offers more evidence that fibre is certainly good for you. Federal dietary guidelines recommend people consume at least 14 grams of fibre per 1,000 calories, so about 28 grams for an average 2,000 calorie-per-day diet. But many experts say many people don’t get enough.

 

More

Olive oil and veggies help the heart

Print pagePDF pageEmail page

It's no secret that eating well is good for both body and mind, so it may not come as a surprise that a new study finds women who eat more olive oil and leafy vegetables such as salads and cooked spinach are significantly less likely to develop heart disease.A group of Italian researchers found that women who ate at least 1 serving of leafy vegetables per day were more than 40 percent less likely to develop heart disease over an average of eight years, relative to women who ate two or fewer portions of those vegetables each week. Women who downed at least 3 tablespoons of olive oil daily – such as in salad dressing – were also 40 percent less likely to be diagnosed with heart disease, compared to women who ate the least olive oil.

It's not exactly clear why specifically leafy vegetables and olive oil may protect the heart, said study author Dr. Domenico Palli of the Cancer Research and Prevention Institute in Florence. “Probably the mechanisms responsible for the protective effect of plant-origin foods on cardiovascular diseases involve micronutrients such as folate, antioxidant vitamins and potassium, all present in green leafy vegetables.” Folate reduces blood levels of homocysteine, Palli explained, which is thought to increase the risk of cardiovascular disease by damaging the inner lining of arteries. Other studies have shown people who eat more potassium have lower blood pressure, which can protect the cardiovascular system. Virgin olive oil may be particularly effective at lowering heart disease risk because of its high level of antioxidant plant compounds, he added.

This is not the first study to link olive oil or vegetables to good heart health. Most famously, the traditional Mediterranean diet — rich in vegetables and monounsaturated fats from olive oil and nuts, but low in saturated fat from meat and dairy — has been tied to a decreased risk of heart disease. Mediterranean-style eating has also been credited with lowering risk for some cancers, diabetes, and, more recently, with slowing brain aging. Cardiovascular disease is a major killer, responsible for 30 percent of all deaths worldwide and the leading cause of death for both men and women in the U.S.

To look more closely at the role of foods in protecting against heart disease, Palli and colleagues reviewed dietary information collected from nearly 30,000 Italian women participating in a large national health study. Researchers followed the women, whose mean age was 50 at the beginning of the study, for an average of 8 years, noting who developed heart disease. In that time, the women experienced 144 major heart disease-related events, such as heart attack or bypass surgery, the authors report in the American Journal of Clinical Nutrition. Women who ate at least one daily serving (about two ounces) of leafy vegetables – such as raw lettuce or endives, or cooked vegetables like spinach or chard — had a 46 percent lower risk of developing heart disease than women who ate at most two portions per week. Consuming at least an ounce of olive oil per day lowered their risk by 44 percent relative to women who consumed a half-ounce or less daily, the authors found.

The women's intake of other types of vegetables, such as roots and cabbages, and their consumption of tomatoes or fruit did not seem to be linked to their risk for major heart events. Both fruits and vegetables have been associated with heart benefits in past studies conducted elsewhere in Europe and in North America. The authors caution that the apparent lack of positive effect from high fruit consumption in their results may have something to do with a different attitude toward fruit in Italy. It is cheap, varied and easily available, so eating a lot of fruit is a widespread habit but it does not necessarily signal that the rest of someone's diet is as healthy, the authors wrote. Another issue with the study, Palli noted, is that women had to report how much they ate of various items, and some may not have remembered their diets accurately, or may have changed their eating habits during the study period. In addition, people sometimes over-estimate their healthy behaviors, believing they eat healthier than they really do.

SOURCE: American Journal of Clinical Nutrition, published online December 22, 2010.

More

Red meat increases women stroke risk

Print pagePDF pageEmail page

Women consuming too much red meat may have a higher risk of stroke than women eating less, says a new study. Red meat is high in saturated fat and cholesterol; both are risk factors for cardiovascular disease, heart attack, and stroke. The United States Centers for Disease Control and Prevention suggests lowering saturated fat intake and eating more fresh fruits and vegetables to help reduce your risk of stroke. Writing in the journal Stroke, researchers examined nearly 35,000 Swedish women, ages 39 to 73. None of the women had heart disease prior to the start of the study in 1997.

After ten years, results showed 4% of the study participants, 1,680 women, had a stroke. Those consuming the most red meat had the highest risk of stroke. Women in the top tenth of red meat intake, consuming at least 3.6 ounces each day, were 42% more likely to have a stroke, compared to women who ate just under one ounce of red meat daily.

Eating processed meat also increased stroke risk. Women eating 1.5 ounces of processed meat each day were 24% more likely to suffer a cerebral infarction, compared to woman consuming less than half an ounce of processed meat each day. Processed meat was not linked to any other form of stroke. Cerebral infarction is a type of stroke caused by a disturbance in the blood vessels supplying blood to the brain. Other types of stroke involve a rupturing of a blood vessel, called hemorrhagic strokes.

The scientists blame red meat and processed meat’s effect on raising blood pressure for the increased stroke risk. According to the World Health Organization (WHO), every year an estimated 17 million people die due to cardiovascular diseases, most notably stroke and heart attack. The WHO lists physical inactivity and unhealthy diet as the main risk factors for heart disease and major cardiac events.

More

Obesity leads to Vitamin D deficiency

Print pagePDF pageEmail page

People who weigh more have lower circulating levels of Vitamin D according to recent research conducted at the Rikshospitalet-Radiumhospitalet Medical Center in Oslo, Norway and published in the Journal of Nutrition. Lead researcher, Zoya Lagunova, MD and her colleagues measured the serum levels of Vitamin D and 1,25(OH)2D in 1,779 patients at a Medical and Metabolic Lifestyle Management Clinic in Oslo, Norway. The associations among 1,25(OH)(2)D, serum 25-hydroxyvitamin D [25(OH)D], and body composition were analyzed. Lagunova noted that generally people with higher BMI had lower levels of Vitamin D. Age, season, and gender were also found to influence serum 1,25(OH)(2)D.

Vitamin D is not a true vitamin, but rather a vitamin-steroid thought to play a key role in the prevention of cancer, cardiovascular disease, diabetes, multiple sclerosis and other diseases. It is likely not coincidental that obesity is also a risk factor for many of these diseases. Vitamin D is vital to the regulation of calcium. Studies have shown that calcium deficiency increases the production of synthase, an enzyme that converts calories into fat. It has been shown that calcium deficiency can increase synthase production by up to 500 percent. Vitamin D has also been shown to play a role in the regulation of blood sugar levels; proper blood sugar regulation is vital to the maintenance of a healthy weight. Vitamin D is produced from sunlight and converted into various metabolites. It is stored in fat tissue. According to Lagunova, obese people may take in as much Vitamin D as other people; however, because it is stored in fat it may be less available. This may result in lower circulating levels of Vitamin D.

A previous study conducted by Shalamar Sibley, MD, MPH, an assistant professor of medicine at the University of Minnesota, showed that subjects who have higher levels of Vitamin D at the start of a weight loss diet lose more weight than those with lower levels. The study measured Vitamin D levels of 38 overweight men and women both before and after following an 11-week calorie-restricted diet. Vitamin D levels at the start of diet was an accurate predictor of weight loss…those with higher levels of Vitamin D lost more weight. It was found that for every nanogram increase in Vitamin D precursor, there was an 1/2 pound increase in weight loss.

Seventy-five percent or more of Americans, teenage and older, are Vitamin D deficient according to a recent study published in the Archives of Internal Medicine. According to the Gallup-Healthways Well-Being Index, 26.5% of American are obese. More research needs to be conducted into the exact role Vitamin D plays in obesity and weight loss and the possibility of increased Vitamin D consumption (through the form of supplementation and/or increased sun exposure) being a key factor to achieving a healthy weight.

More

Tomatoes Fight Cholesterol

Print pagePDF pageEmail page

If you want to wage battle against cholesterol and other lipids (fat) that can contribute to vascular disease, then make tomatoes a big part of your diet. Scientists say this popular fruit contains a nutrient that can fight vascular disease such as stroke and arteriosclerosis.

tomatoes_2

Tomatoes fight more than cholesterol and fat

Excessive levels of lipids, such as cholesterol and triglycerides in the bloodstream, a condition known as dyslipidemia, can lead to potentially deadly diseases such as arteriosclerosis, cirrhosis, and stroke. Scientists from Kyoto University and New Bio-industry Initiatives, Japan, report that a compound called 9-oxo-octadecadienoic extracted from tomatoes can boost oxidation of fatty acids and contribute to the regulation of lipid metabolism by the liver. These qualities indicate that 9-oxo-octadecadienoic acid can fight cholesterol and other lipids and therefore help prevent vascular diseases.

Vascular disease is a general term used to describe diseases that affect the blood vessels. The Vascular Disease Foundation offers information on nearly two dozen different conditions that fit this category, including abdominal aortic aneurysm, carotid artery disease, deep vein thrombosis, lymphedema, peripheral artery disease, and stroke.

Tomatoes are also valued for other health benefits. Much research has been dedicated to a potent antioxidant in tomatoes, lycopene, and its potential in the fight against various types of cancer, and especially prostate cancer. Tomatoes also contain excellent levels of other nutrients, including niacin, which helps lower cholesterol; and potassium, which reduces blood pressure and the risk of heart disease.

Dr. Teruo Kawada, who is from Kyoto University and who led the study, noted that “Finding a compound which helps the prevention of obesity-related chronic diseases in foodstuffs is a great advantage to tackling these diseases. It means that the tomato allows people to easily manage the onset of dyslipidemia through their daily diet.” To help the fight against cholesterol and other fats that contribute to vascular disease, enjoy more tomatoes.

SOURCES:
Kim YI et al. Molecular Nutrition & Food Research doi:10.1002/mnfr.201000264

More

Does milk fight bowel cancer

Print pagePDF pageEmail page

The study was carried out by researchers from University of Otago Medical School, New Zealand. Funding was provided by Genesis Oncology Trust, the Dean’s Bequest Funds of the Dunedin School of Medicine, the Gisborne East Coast Cancer Research Trust and the Director’s Cancer Research Trust. The research was published in the peer-reviewed American Journal of Epidemiology. This was a case-control study in New Zealand that compared a group of adults with bowel cancer, and a group without bowel cancer, and looked at whether they drank milk at school. School milk was freely available in most schools in New Zealand until 1967 when the government programme was stopped. Many schools in the Southland region stopped free milk as long ago as 1950.

Case-control studies are appropriate for looking at whether people with and without a disease have had a particular exposure (milk in this case). The difficulty is in accounting for all potential confounding factors, particularly other health and lifestyle factors, which could be related to both diet and bowel cancer risk, for example regular childhood milk consumption could be a reflection of a ‘healthy’ diet and other healthy lifestyle behaviours that may reduce risk of cancer. In addition, when examining such a specific dietary factor – ie milk consumed in school – it is difficult to account for all possible milk or other dairy products consumed outside of school.

In this case-control study, 562 adults (aged 30 to 69) with newly diagnosed bowel cancer were identified from the New Zealand Cancer Registry in 2007. For a control group, 571 age-matched adults without cancer were randomly selected from the electoral register. All participants were mailed a questionnaire that asked about any previous illness, use of aspirin or dietary supplements in childhood, participation in school milk programmes, other childhood milk consumption, childhood diet (including other milk and dairy), smoking, alcohol consumption prior to 25 years of age, screening tests for bowel cancer, family history of cancer, education and sociodemographic characteristics. Childhood weight and height were not questioned. For school milk consumption they were specifically asked:

  • Whether they drank school milk
  • How many half-pint bottles they drank a week
  • What age they first drank school milk
  • When they stopped drinking school milk

Statistical risk associations between school milk participation and cancer were calculated. The calculations took into account several risk factors for bowel cancer risk including age, sex, ethnicity and family history.

What were the basic results?

Data on school milk consumption was available for 552 cases and 569 controls. As expected, people who started school before 1967 were more likely to have had free school milk than those who began school after 1968. Seventy-eight percent of cases participated in the school milk programme compared with 82% of controls. School milk consumption was associated with a 30% reduced risk of developing bowel cancer (odds ratio 0.70, 95% confidence interval 0.51 to 0.96).

When looking at the effect of number of bottles consumed per week they found that compared with no bottles, five bottles per week was associated with 32% significantly decreased risk, and 10 or more bottles with 61% significantly decreased risk. However, there was no significant association with one to four bottles or six to nine bottles. The researchers found a similar trend when the total school consumption of milk was compared with no consumption: 1,200-1,599 bottles was associated with 38% significantly decreased risk; 1,600-1,799 with 43% decreased risk; and 1,800 or more bottles associated with 38% significantly decreased risk. There was no significant association with fewer than 1,200 bottles. The researchers calculated that for every 100 half-pint bottles consumed at school there was a 2.1% reduction in the risk of bowel cancer. Outside of school, there was a significantly reduced risk of bowel cancer with more than 20 dairy products a week compared with none to nine dairy products a week.

The researchers conclude that their national case-control study ‘provides evidence that school milk consumption was associated with a reduction in the risk of adult colorectal cancer in New Zealand. Furthermore, a dose-dependent relation was evident’. This study has strengths in its relatively large size, its reliable and nationally representative identification of cases and controls, and its thorough data collection. However, the conclusion that school milk consumption is associated with a reduced risk of bowel cancer in adulthood must be interpreted in light of a number of considerations:

The analysis took into account established risk factors for bowel cancer including age, sex, ethnicity and family history. However, many other potential confounders were not considered, including diet, physical activity, overweight and obesity, smoking or alcohol consumption. Diet in particular has been implicated in bowel cancer risk, with diets high in saturated fat, red meat and processed foods and low in fibre, fruit and vegetables thought to increase risk. Potentially, any of these lifestyle behaviours could be confounding the relationship between school milk consumption and bowel cancer and regular childhood milk consumption could be a reflection of a ‘healthy’ diet and other healthy lifestyle behaviours that reduce risk of cancer. When looking at the effect of number of bottles consumed per week, the researchers found that, compared with no bottles, five bottles were associated with 32% significantly decreased risk and 10 or more bottles with 61% significantly decreased risk. However, there was no significant association with one to four bottles or six to nine bottles. Therefore, the trend here is not very clear. Particularly as only 16 cases and 31 controls drank 10 or more bottles a week, statistical comparison between such small numbers should be viewed with caution. With many food questionnaires there is the potential for recall bias. For example, adults may have difficulty remembering how many bottles of school milk they drank many years before. When estimating their average weekly amount, it is highly possible that this could be inaccurate or that their consumption varied slightly from week to week and year to year. Particularly when researchers were using this response and combining it with the number of weeks in the school year and their total years at school to give a total number of bottles consumed at school (figures in 100s or 1,000s), there is the possibility of being incorrectly categorised. Hence, there may be less reliability when calculating risk according to the category of total milk bottles consumed. Cancer prevalence, and particularly environmental and lifestyle risk factors for cancer, can vary between countries. These findings in New Zealand may not be represented elsewhere. Of note, the researchers acknowledge that a cohort study in the UK found the opposite: increased childhood dairy consumption was associated with increased risk of bowel cancer. Case-control studies are most appropriate for looking at rare diseases, where you would expect there to be only a small number of cases developing among a large number of people. In the case of bowel cancer, which is common, the slightly more reliable cohort design could have also been used, where children who drank milk at school and those who didn’t were followed over time to see if they developed cancer. However, such a cohort would consequently need extensive long-term follow-up.

The possible association between milk/dairy consumption, or calcium intake, in childhood, or in later years, is worthy of further study. However, from this study alone, it cannot be concluded that school milk prevents bowel cancer later in life.

More