Trying to eat a healthier diet? Get to a target weight? Or just make sense of all the nutrition news out there?

Globe columnist and dietitian Leslie Beck was online earlier to take your questions on healthy eating, boosting nutrition and everything in between.

Your questions and Ms. Beck's answers appear at the bottom of this page.

A leading Canadian nutritionist, Ms. Beck operates a private practice in Toronto. When she's not helping people achieve their nutrition and fitness goals, she's writing her weekly column for The Globe and making appearances on CTV as Canada AM's nutrition expert.

Ms. Beck is the author of seven books, including her most recent release, Foods that Fight Disease (Penguin, January, 2008).

Born and raised in Vancouver, Ms. Beck obtained her Bachelor of Science (Dietetics) from the University of British Columbia and proceeded to complete the dietetic internship program at St. Michael's Hospital in Toronto. She studied a Masters in Epidemiology at the University of Toronto. She is a member of Dietitians of Canada and the College of Dietitians of Ontario.

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Lily B from Toronto Canada writes: I am in my early twenties. My family has a strong history of osteoporosis. Should I be taking a calcium supplement? If so, what should I look for in a supplement? Is it necessary to take one with vitamin D? I try to eat a lot of yogurt, but I hate the taste of milk, so most of my milk intake is through lattes.

<>Leslie Beck: Hi Lily, You require 1000 milligrams of calcium every day. (If you have had your bone mineral density measured, and your doctor has told you it is low, then you should increase your calcium intake to 1500 milligrams per day.) In food terms, 1000 milligrams of calcium is provided in 3 servings of milk or milk alternatives (e.g. 1 cup milk, 3/4 cup yogurt, 1.5 ounces of cheese or 1 cup soy beverage). One cup (250 ml) of milk, 175 ml plain yogurt or 1.5 ounces (45 grams) of cheese delivers roughly 300 milligrams of calcium, as does one cup (250 ml) of enriched soy beverage or fruit juice.

Almonds, leafy greens and cooked broccoli also add calcium to your diet but in smaller amounts. Canned salmon is also a good source but only as long as you eat the bones.

So, if you are not consuming 3 servings of dairy or fortified beverages every day, then yes, you should take a calcium supplement. The most common calcium supplements are calcium carbonate and calcium citrate. Calcium carbonate supplements are generally the least expensive and most widely used; each provides roughly 500 milligrams of calcium per tablet. Calcium citrate supplements are lower dose; they contain 300 to 350 milligrams of calcium per tablet. Calcium carbonate must be taken with a meal, whereas calcium citrate can be taken with food or on an empty stomach.

Many people find calcium carbonate products are more convenient. That's because you'd have to take more calcium citrate pills to get the same amount of elemental calcium as you'd get from a calcium carbonate pill.

Vitamin D is necessary for the absorption of calcium. I generally advise choosing a calcium supplement with added vitamin D. You should be consuming 1000 IU of vitamin D each day for cancer prevention and bone health. Add up how much supplemental vitamin D you are getting from your multivitamin (if you take one) and calcium supplement(s). If necessary, make up the difference with a separate vitamin D supplement.

Magnesium is also important for bone health but it is not necessary to help the body absorb calcium. Magnesium rich foods include whole grains, legumes, nuts, leafy greens, dried fruit and dairy products. If you opt for a calcium-magnesium supplement, choose one with a 2:1 ratio of calcium and magnesium (e.g. 300 milligrams of calcium and 150 milligrams of magnesium). Taking supplemental magnesium in doses of 350 milligrams or greater can cause diarrhea.

One last tip: spread your calcium intake over the course of the day. Absorption from supplements is best in doses of 500 milligrams or less.

Jeff Bakker from Toronto Canada writes: Hi Leslie,

My father has been diagnosed with a very high level of iron in his blood. To help reduce his iron levels, what are some of the foods that he should avoid? We know that spinach, swiss chard, and kale should be avoided, but are there other food items that he should pass on?

Thanks
Jeff

Leslie Beck: Hi Jeff, There are two types of iron in foods: heme iron from animal food (meat, poultry, fish, seafood, eggs). Foods that are rich in this type of iron should be avoided and they include beef, liver, trout, oysters, calms and sardines. Heme iron is absorbed and utilized the most efficiently by the body. Non heme iron is found in plant foods such as whole grains, legumes, fruits and vegetables. The body is much less efficient in absorbing this type of iron. Good sources of non-heme iron include spinach, nuts, legumes (kidney beans, navy beans, etc) and dried fruits such as raisins, prunes and apricots. Although the body does not absorb as much of this iron as it does from meat, there are two ways you can reduce the amount of iron your body does absorb from them:

Avoid eating a vitamin C rich food with iron-rich plant foods (e.g. citrus, kiwi, broccoli, red pepper, tomato juice, etc.). Vitamin C enhances the body's ability to absorb non-heme iron.

Drink coffee or tea with a meal that contains iron (e.g. spinach, ready-to-eat breakfast cereal, legumes). Compounds in these beverages inhibit the absorption of iron.

Your father should also avoid iron in supplements. He should take an iron-free multivitamin and mineral supplement.

I Yappa from Canada writes: What is your recommendation on how many eggs an adult should eat per week, assuming they're eating Omega-3 eggs? And please say why (eg concerns about cholesterol or fat).

Leslie Beck: Great question! There is so much confusion about eggs. The concern with eggs has to do with their high cholesterol content — 190 milligrams per one egg. Nutrition guidelines to keep LDL blood cholesterol in the desirable range have emphasized limiting dietary cholesterol — abundant in egg yolks, shrimp, liver and duck — to less than 300 milligrams per day. (Elevated LDL cholesterol in the bloodstream is a major risk factor for heart disease.) The Heart and Stroke Foundation of Canada does not recommend a specific cholesterol intake for healthy people but rather stresses the importance of limiting saturated and trans fats to help control blood cholesterol.

That's because higher intakes of saturated fat (found in fatty meats, poultry and dairy products) and trans fats (found in baked goods, snacks, and fried foods made with partially hydrogenated vegetable oil) raise LDL cholesterol much more than do higher amounts of dietary cholesterol.

While there's compelling evidence that high cholesterol intakes can cause hardening of the arteries in animals, there's little evidence that this is so in humans. For most people, only a small amount of cholesterol in food passes into the bloodstream. What's more, studies conducted in healthy men and women have found that eating one egg per day does not increase the risk of heart attack or stroke. However, a recent study suggests that people with diabetes might want to limit egg yolks to four per week. In the study, people with diabetes who ate 7 or more eggs per week versus less than one had a twofold greater risk for all cause mortality, presumably from heart disease. It's thought that individuals with diabetes absorb higher amounts of cholesterol from foods.

Bottom line: If you're healthy, one whole egg a day seems perfectly safe. And yes, look for omega-3 eggs that are enriched with DHA, the omega-3 fatty acid found in oily fish. Increasing DHA intake may help reduce the risk for heart disease and possible, age-related dementia.

Mowho33 Who from Canada writes: I'm 44 yrs old. I'm very active - I've exercise about 250 minutes per week and burn about 2500 cals per week in various cardio exercise - running, biking, hiking etc. I've built up to this level over the course of about a year. I'm over half way to my weight loss goal of 52 lbs. (I've lost 27 lbs since Dec 2007) I've noticed my weight loss is slowing and I recently suffered about a 3 week plateau, which continued despite me eating less than ever before to try to bust it. I began to suspect that my body was going into starvation mode, if such a thing exists, and I started feeling grumpy and like quitting, so I started to eat more. I may have come out of the plateau a bit by eating more, but it's too soon to tell.

How do you counsel people to bust their plateaus? And how much of a caloric deficit do you recommend that people try to attain? I've probably been at a deficit between 500 or 1000 cals per day?

Leslie Beck: Your daily calorie deficit sounds fine. What is more important is the total number of calories you are consuming each day relative to how many you are burning off through exercise. If you consume too few calories, your body can go into a "starvation" mode in which it holds on to its reserves because it thinks it might not be getting calories for awhile. So think about your calorie intake and expenditure to determine if this might have been the cause of your plateau.

But there are other reasons for plateaus. A weight loss plateau is when you were losing weight and then stopped losing, without changing your diet, exercise or other lifestyle factors. Plateaus are frustrating but they are a normal, natural part of the weight loss process. They often occur when you reach a weight that you have not been below for quite some time. As you lose weight, your body requires fewer calories and your rate of weight loss may temporarily slow down.

It takes persistence and consistency to break through a plateau. The key is not giving up. If you say to yourself it doesn't matter what you eat because your weight isn't budging, you'll never break though that number on the scale. I do not advise that you eat less food in order to speed up your weight loss. Instead, the best way to work through a plateau is to notch up your exercise to burn more calories. If you've been doing the same workout routine for months, it's time to challenge your body. Consider cross training by adding different types of cardiovascular workouts to your weekly routine. Or, it might be time to add strength training exercises to your program. Strength training helps build more muscles to rev up calorie burning.

Alan Yeadon from Surrey, BC Canada writes: Currently, my blood cholesterol levels are normal; however, the levels are slowly increasing (HDL slowly decreasing). I currently take 1500mg. of Niacin daily and my daily diet is considered appropriate, i.e. vegetables, fruit, little red meat, etc.. Are there other dietary suggestions for improved blood cholesterol levels ?
Thanks, Alan

Leslie Beck: Hi Alan, First of all, I am going to assume that the niacin you are taking has been prescribed by your physician. High doses of the B vitamin niacin bought at a healthy food store are not recommended for cholesterol lowering. They are not effective and should not be used for cholesterol lowering without the monitoring of your doctor because of the potential side effects.

The best way to lower LDL cholesterol is to reduce your intake of animal fat (saturated fat) and trans fats. To reduce saturated fat, choose lean meat, skinless poultry breast, and low fat dairy products (1% MF or less). Use butter sparingly. If you eat a lot of cheese, cut back. The most cholesterol-raising type of saturated fat is the type found in high fat dairy products (cheese, cream, butter, ice cream). To limit trans fats reduce your intake of French fries and commercial bakery goods (muffins, Danish, pastries, cookies). Read the Nutrition Facts box on packaged foods; choose ones that have little or no trans fat. Foods with a 5% (or less) Daily Value for saturated + trans fat will be low in these bad fats.

Adding a good source of soluble fibre to your daily diet will also help bring your LDL cholesterol down. Soluble fibre is in oatmeal, oat bran, and psyllium-enriched breakfast cereals. Nuts have also been shown to help lower cholesterol. Try eating 1/4 cup (a small handful) of plain almonds or walnuts with a piece of fruit for an afternoon snack.

Cardiovascular exercise (at least 4 days per week) and weight loss (if appropriate) can help to increase your HDL cholesterol.

Peter Cricel from Canada writes: Do you know of one book or website (or best combination) that gives a complete breakdown of the nutritional components of most foods in their cooked and raw states; i.e. protein, fats - broken down into the various kinds, vitamins, sugars, calories etc?

Thank you, Peter

Leslie Beck: Hi Peter, Here you go. One is the Canadian Nutrient File, 2007 version and the other is the USDA National Nutrient Database. I routinely use both.

http://205.193.93.51/cnfonline/newSearch.do

http://www.nal.usda.gov/fnic/foodcomp/search/

Have fun!

Seymore Applebaum from Toronto Canada writes: What are the health risks associated with eating too much red meat?

Leslie Beck: Depending on what cuts of meat you choose, you could be consuming excess saturated fat that raises LDL blood cholesterol, a risk factor for heart attack and stroke.

But by far the biggest concern is that high intakes of red meat are associated with a greater risk of colon cancer. Many studies show that people who eat the most red meat (beef, veal, pork, lamb) and/or processed meat (luncheon meat, bacon, hot dogs, sausages) are more likely to get colon cancer than those who eat these foods only once in awhile.

Meat might boost colon cancer risk in a few ways. In lab animals, compounds formed when meat is cooked have been shown to cause colon tumours. The form of iron in red meat — heme iron — may also damage colon cells and trigger cancer growth. And it's thought that nitrites in some processed meats may form cancer-causing compounds in the body.

Cancer experts now advise that you limit your intake of fresh red meat to a maximum of 18 ounces per week and that you avoid processed meat. Choose fish, chicken, turkey, legumes, tofu and soy foods more often than meat.

A Tse from Canada writes: When do you recommend that an infant start drinking whole milk? Some sources suggest starting at 9 months, while others suggest 12 months. In comparing whole milk to formula, what nutrients are missing in whole milk that are available in formula? Thanks in advance.

Leslie Beck: Most experts advise waiting until 9 months of age to introduce an infant to cow's milk. However, when it comes to preventing food allergies, eczema and asthma, you might want to hold off until after your child turns one. If there is an allergy in your baby's immediate family (e.g. you, your partner, or another child), I definitely recommend that you wait one year before you gradually introduce cow's milk into your child's diet. If you are not breastfeeding, then I recommend you choose an infant formula with DHA, an omega-3 fatty acid needed for brain and eye development during infancy.

There are other foods you should hold off introducing until after your child's first birthday, especially if your child has not been breastfed (or if there is a family history of allergies). You must not offer egg whites until after one year — that's a must for every child. But other potentially allergic foods include cow's milk (as mentioned above), nuts and nut butters, soy foods, wheat, corn, fish, seafood, and citrus fruit.

Rasha Mourtada, Globe Life web editor: Thank you, Leslie, for coming online. To our readers, we're sorry we didn't get to all of your questions today. Please look out for future discussions with Leslie Beck.