Oat bran and other types of soluble fiber can lower cholesterol
How healthy is your heart? Young or old, all of us can benefit from taking stock of our dietary habits, especially when it comes to keeping the old ticker in good shape. You already know the basics: Fruits and vegetables are great options, as are lean meats and fish. A handful of nuts a day is a smart choice; so is cutting down on refined carbohydrates, trans fats and high-sodium foods. But what about less well-known but potentially heart-healthy options, such as flaxseed or psyllium fiber? Do they offer hope or just hype?
February is Heart Month, so it’s a good time to take a look at the influence certain foods and supplements can have on heart health. Here, we'll focus on different sources of soluble fiber, a type of fiber often recommended for controlling cholesterol levels.
You may remember the hoopla in the 1980s surrounding oat bran. It died down for a decade or so, but now oat bran is back, probably for good. In numerous clinical trials, oat bran, a key component of old-fashioned oatmeal, has demonstrated a consistent capacity to lower cholesterol, largely because of a compound it contains known as beta-glucan, which is a type of soluble fiber that can bind cholesterol in the digestive tract, causing it to be excreted as waste.
For some, getting more oat bran is as simple as switching from cold cereal to oatmeal – an appealing option in the middle of winter. You can also buy oat bran at the grocery store and sprinkle it on your regular cereal, in yogurt or in a smoothie. (Oat bran is also particularly rich in vitamin E.) Another alternative is to choose a cold cereal that contains oat bran – General Mills' Cheerios being one popular choice, for example.
Flaxseed oil isn’t as good as fish oil when it comes to heart health. But eating ground flaxseed does make good sense for your heart. In human studies, the addition of a daily dose of ground flaxseed can result in LDL, or "bad" cholesterol, reductions of 9 percent to 18 percent for those with normal cholesterol levels, and 4 percent to 10 percent for those with high cholesterol. The key point is this: While ground flaxseed contains soluble fiber, as well as cholesterol-lowering compounds known as lignans, flaxseed oil does not.
If you're considering adding ground flaxseed to your diet, the best way to do so is to use cold-milled ground flaxseed, or buy the whole seeds and grind them yourself. Ground flaxseeds are delicate and must be treated with care: Once ground, they need to be kept in a cold, dark place (i.e. the fridge), or else the fats will become rancid within just a few hours. For cholesterol control (not to mention bowel health), try adding one to two tablespoons per day to cereal, oatmeal or yogurt.
Oddball spelling aside (the "P" is silent), psyllium fiber is another soluble fiber that has a well-documented capacity to lower cholesterol. Derived from psyllium husks (which you can buy directly), psyllium fiber is also found in powdered form, such as in Metamucil, the popular digestive aid. There are also a select number of cold cereals that contain psyllium fiber, in particular Kellogg's All-Bran Buds (not to be confused with regular All-Bran, which does not contain psyllium), All-Bran Guardian and Smart Bran by Nature's Path. Regardless of the source, the evidence suggests that consuming psyllium on a daily basis can lower LDL cholesterol, with one meta-analysis (a compilation of results from several different studies) demonstrating an average 9 percent reduction in LDL cholesterol after four weeks on a psyllium-fiber cereal.
The Bottom Line
Adding soluble fiber to your diet, whether as oat bran, ground flaxseed or psyllium fiber or in other forms – such as fruit, beans, barley or soybeans – is a tried, tested and generally safe way to control your cholesterol. When increasing your intake, however, make sure to do so gradually and drink plenty of water to prevent excess gas, bloating or abdominal discomfort. Also, because some types of fiber, particularly psyllium fiber, can reduce absorption of certain medications, you should speak with your physician before starting a new supplement regimen.
This column was written by Jennifer Sygo, Director of Nutrition for Cleveland Clinic Canada, which offers executive physicals, prevention and wellness counseling and personal healthcare management in Toronto. It originally appeared in The National Post on Feb. 1, 2010. Reprinted with permission.
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