Tuesday, October 30, 2012
You can get sufficient amounts of both iron and calcium by eating whole, natural foods that are rich in these two minerals and part of a balanced, consistent Healthiest Way of Eating. Fortunately for all of us, whole, natural foods have evolved in such a way as to meet our nutrient needs provided that we do our part to consume them in a balanced and responsible way.
With respect to interactions between calcium and iron, let me address possible absorption problems from one perspective at a time. First, when it comes to calcium inhibition of iron absorption, I've seen several research studies showing clear, dose-dependent reductions in iron absorption following addition of calcium to a meal or to foods themselves. These reductions in iron absorption involved both plant (non-heme) and animal (heme) forms of iron, and were in the general range of 50%. While these studies definitely warrant more follow-up, I am reluctant to draw major conclusions from them about the interaction between these two minerals when it comes to whole, natural foods.
From my perspective, it is very different to add supplemental calcium to foods and examine the effects on iron absorption than it is to start with naturally high-calcium, non-supplemented foods and look at their impact on iron. In studies that I have seen on natural foods and long-term iron status, there does not appear to be any significant lowering of iron absorption when iron-rich foods and calcium-rich foods are consumed simultaneously. Over the long run, our bodies seem well equipped to handle both minerals simultaneously from the standpoint of iron absorption from whole, natural foods.
With respect to iron inhibiting calcium absorption, I have seen in vitro laboratory studies that show calcium absorption to be blocked when excessive amounts of iron have been allowed to accumulate in the spaces surrounding our cells. These lab studies, while extremely important, do not address the issue of iron and calcium that have been naturally stored up inside of food and are trying to make their way from food up into the body. The only studies that I have seen in this area of iron impact of calcium absorption have involved mineral supplements rather than whole foods. That being said the evidence in these studies points consistently in the direction of very little impact of iron on calcium absorption.
There is active transport of calcium from the upper parts of the small intestine into the cells lining the intestinal tract when calcium intake is very low, and this process is very carefully regulated. There is also passive transport of calcium lower down in the digestive tract that takes place under conditions of normal or high intake of calcium. I would expect this passive process to be influenced by a variety of minerals present in the lower small intestine, but I once again have found no evidence that separation of high-iron foods and high-calcium foods (or high-calcium foods and iron supplements) would be necessary to obtain beneficial amounts of both minerals.
For more information on this topic, please see:
George Mateljan Foundation, PO Box 25801, Seattle, Washington 98165
Tuesday, October 23, 2012
Wednesday, October 17, 2012
Tuesday, October 16, 2012
Monday, October 15, 2012
Wednesday, October 10, 2012
Mekar sejambak bunga melati,
Kembang menghias serambi rumah,
Menambat seri hati penghuni;
Usah diturut kata hati,
Jangan terdorong nafsu amarah,
Kelak binasa diri sendiri.
Menuruni bukit terus ke lembah,
Menghijau pepohon nan merimbun;
Jangan diulangi kesilapan Al'qomah,
Bimbang tak sempat bermohon ampun.
Berseri sanggul dek bunga sekuntum,
Berkebaya labuh menyerlah keanggunan;
Sahabat nabi lagi terhukum,
Inikan pula kita orang kebanyakkan.
Berpantun berseloka adat orang kita,
Penuh pujian mau pun sindiran;
Terlalu mulia kedudukan ibubapa,
Termaktub dalam hadith dan alquran.
Terhampar langit tiang tiada,
Dihias bulan bintang mentari;
Berdamailah rendahkan hati kita,
Monday, October 8, 2012
I find that I snack a lot. What are your suggestions as to how I can tide myself over between meals?
If you're trying to reduce the amount of food you eat between meals, there are several things to consider.
Snacks should provide a balance of nutrients
The first is to make sure that your meals contain an appropriate amount of protein, fiber, and accompanying nutrients. This will help to satiate your appetite so that you will be less hungry between meals.
You also want to make sure that your meals don't contain an excessive amount of fat or simple sugars. Excessive fat can slow down your digestion to the point where it takes too long for you to derive energy and nourishment from your food. Excessive sugar can digest too quickly and leave you too quickly ready for more food.
Timing of snacks
You'll also want to ensure that you don't wait too long between meals because it's difficult to avoid overeating if you go longer than four to five hours between meals. It is best to have smaller meals more frequently throughout the day rather than larger ones two to three times a day (please remember this means mini-meals filled with nutrient-rich foods rather than eating nutrient-depleted junk food snacks every several hours). If small frequent meals won't work for your schedule, you'll want to ensure that the snacks that you eat between meals are filling and nutritious.
Vegetables and dips make healthy snacks
Vegetable crudités are some of the most healthy and easy snacks to prepare. Cut up small pieces of your favorite vegetables and enjoy them with a small amount of dip made with extra virgin olive oil or low-fat yogurt. I like the idea of a low-fat yogurt since it boosts up the protein content and increases the "holding power" of the snack. Bean dips would work in this exact same way, and are even higher in protein and fiber than dips made using yogurt. Small amounts of nut or seed butters-like almond butter or sesame seed butter (tahini)-would also help to build the fiber and protein content of a dip as well as bring small-to-moderate amounts of dietary fat into your snacks. From my perspective, when kept moderate, this added fat can be a good thing for slightly slowing the digestive process and stretching the snack's impact. But it's also important not to overdo things, and push your snack calories upward all the way to meal level.
Ideas for vegetable selection include (but are definitely not limited to) zucchini sticks, baby carrots, bell pepper slices, and cauliflower and broccoli florets. Even though it is not highly time-consuming to do the cutting and chopping of these vegetables yourself, you might want to consider the added convenience of pre-chopped and pre-sliced vegetables. Many stores offer organically grown, pre-cut vegetables that could provide just the right amount of extra convenience to get you going on some improved snack options. In any case, you'll get a variety of nutrients from these vegetable-plus-dip combinations and have your appetite satisfied by a reasonable number of calories.
Also, design your meals so that you experience them as pleasurable and relaxing (for example, eat more slowly, light some candles, and unplug the telephone). If meals are a chaotic experience and not enjoyable, you are less likely to be satiated both physically and emotionally and you will more likely want to eat again soon afterwards.
I'd also like to add one last set of observations about individuals who find they snack too frequently. It's important to think about the pattern of your entire day in terms of enjoyment and activities. You may or may not want to make healthy snacking the solution to a daily pattern that just isn't working for you in terms of balance and enjoyment. In some cases, planning a larger, more nourishing meal before a difficult snack period time-and then shifting activities to turn a former snack period into a period of time focused on other enjoyable pursuits-can be a more effective way of "tiding yourself over" than experimenting with your snack content.
Copyright © 2012 The George Mateljan Foundation, All Rights Reserved
George Mateljan Foundation, PO Box 25801, Seattle, Washington 98165