SUPPLEMENTS MAY DO MORE HARM THAN GOOD
The most commonly
consumed vitamin and mineral supplements provide no consistent health
benefit or harm, suggests a new study published in the Journal of the American College of Cardiology
led by researchers at St. Michael's Hospital and the University of
Toronto.
“We were surprised to find so few positive effects of the most common
supplements that people consume,” said Dr. David Jenkins, the study's
lead author. “Our review found that if you want to use multivitamins,
vitamin D, calcium or vitamin C, it does no harm - but there is no
apparent advantage either.”
The study found folic acid alone and B-vitamins with
folic acid may reduce cardiovascular disease and stroke. Meanwhile,
niacin and antioxidants showed a very small effect that might signify an
increased risk of death from any cause.
“These
findings suggest that people should be conscious of the supplements
they’re taking and ensure they’re applicable to the specific vitamin or
mineral deficiencies they have been advised of by their healthcare
provider,” Dr. Jenkins said. “In the absence of significant positive
data - apart from folic acid's potential reduction in the risk of stroke
and heart disease – it’s most beneficial to rely on a healthy diet to
get your fill of vitamins and minerals.”
Writing in The
Conversation, Prof Clare Collins says: “Most people in Western
countries don’t have an optimal diet. This review shows taking
supplements as an “insurance policy” against poor dietary habits does
not work. If it did, there would have been a reduction in early death …
The bottom line is we need to eat more nutrient-rich whole foods,
including foods high in folate such as green leafy vegetables, legumes,
seeds, poultry, eggs, cereals and citrus fruits. Many breads and
breakfast cereals in Australia are fortified with folate. Good food
sources of niacin (vitamin B3) are lean meats, milk, eggs, wholegrain
breads and cereals, nuts, leafy green vegetables and protein-containing
foods.”
Read more:
- Supplemental Vitamins and Minerals for CVD Prevention and Treatment
- Prof Clare Collins: New Vitamin supplement study find they may do more harm than good
Over the past twenty years, Dr Neal Barnard has undertaken a number of studies looking specifically at the benefits of vegetarian and vegan diets for people with type 2 diabetes. “A plant-based diet is the preferred approach to type 2 diabetes,” he says. “It is easy, effective, and all the ‘side-effects’ are good ones—weight loss, better blood pressure and cholesterol, and less need for medications.”
In a 74-week randomised trial, 99 adults with type 2 diabetes were placed on either a vegan diet or the 2003 American Diabetes Association (ADA) diet guidelines, which emphasised limiting calories and controlling carbohydrates. The vegan diet proved better at controlling BGLs and cholesterol. After an additional year of observation, the vegan group still had an edge when it came to controlling blood glucose and cholesterol.
A 10-city study conducted at GEICO plants around the US again showed that a vegan diet can improve body weight and blood glucose control. The researchers found that it is also promising for people with advanced diabetes. A randomised controlled pilot study showed that a low-fat vegan diet led to substantial improvements in painful diabetic neuropathy.
Research scientists know that adhering to all therapeutic diets requires some effort by the participants. Dr Barnard’s team has specifically monitored the acceptance of the vegan diet and reports that it appears to be no more challenging than other prescribed diets for people with type 2 diabetes.
In a 2014 systematic review and meta-analysis of 255 people (average age 42.5 years) followed for an average of 24 weeks (range 4–74 weeks) his team found that vegetarian diets were associated with improved glycemic control in people with type 2 diabetes – a significant 0.39% reduction in HbA1c.
Read more:
- 74-week randomised trial
- 10-city study
- Randomised controlled pilot study
- Acceptance of the vegan diet
- Systematic review and meta-analysis
Of the 1764 women diagnosed with breast cancer during the Women's Health Initiative Dietary Modification trial, those following a lower-fat diet had increased breast cancer overall survival, although the increase was likely partly due to better survival from several causes of death. In the trial, 19,541 women followed a dietary intervention to reduce their fat intake to 20 percent of calories and increase the amount of fruits, vegetables and grains they were eating, while 29,294 women served as a usual-diet comparison group.
Read more:
CUT BACK SAT FAT TO REDUCE DIABETES RISK
Nonalcoholic fatty liver disease is a risk factor for type 2 diabetes and cardiovascular disease. In this small and short-term overfeeding study, the researchers gave overweight people an extra 1000 calories a day from saturated fat, unsaturated fat and carbohydrates (simple sugars). They found that where the extra calories came from made a difference to increases in IHTG (intrahepatic triglyceride). Saturated fat induced greatest increase in IHTG, insulin resistance, and harmful ceramides. They suggest that decreased intakes of saturated fat could be beneficial in reducing IHTG and the associated risk of diabetes.
Read more:
TWO RELIABLE REFERENCES
Catherine Saxelby’s Complete Food and Nutrition Companion (second edition) A leading nutritionist for over 25 years, Catherine has educated a generation of Australians about healthy eating and getting the most from their diet. This A–Z guide is a practical family nutrition reference with more than 500 entries covering whole foods, processed foods, additives, nutrients, supplements and more.
Understanding the Science of Food from Molecules to Mouthfeel. Sharon Croxford and Emma Stirling wrote this as a food science text book. But anyone interested in food science will enjoy it. They describe the key processes in food preparation and the chemistry behind them in detail including denaturation and coagulation of proteins, gelatinisation, gelation and retrogradation of starches, thickening and gelling, browning reactions, emulsification, foams and spherification, chemical, mechanical and biological leaveners and fermentation and preservation. They also cover the science behind cooking techniques and the senses.
