Soluble fibre in psyllium, oat bran and flax seeds may help lower disease risk
Remember those health kicks of the 1980s that encouraged everyone to eat oatmeal? They're back, with even more research backing up oat bran's cholesterol-lowering capabilities.
Photograph by: Handout / Canwest file photo, National Post
How healthy is your heart? Young or old, everyone can benefit from taking stock of their dietary habits, especially when it comes to keeping the old ticker in good shape. You probably 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, as is cutting down on refined carbohydrates, trans fats and high-sodium foods. But what about less well-known, but potentially heart-healthy options, like flaxseed or psyllium fibre? Do these functional foods and supplements offer hope, or just hype?
February is heart month, so we’ll be taking a closer look at the influence functional foods and supplements can have on heart health. This week, we’ll focus on different sources of soluble fibre, a type of fibre often recommended for controlling cholesterol levels.
OAT BRAN IS BACK
Readers who remember the 1980s well can probably recall the hoopla surrounding oat bran. After petering out for a decade or so, 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 fibre that can bind cholesterol in the digestive tract, causing you to excrete it 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 yogourt or in a smoothie. (Oat bran is also particularly rich in vitamin E, a difficult-to-get vitamin many Canadians miss in their diet). Another alternative is to choose a cold cereal that contains oat bran — General Mills’ Cheerios being one popular choice, for example.
FLAX: FOR BETTER OR WORSE?
In the past, I’ve recommended fish oil over flaxseed oil, especially for heart health. As the reasoning goes, both flax and fish contain essential omega-3 fatty acids, but the types of omega-3s in fish, known as DHA and EPA, have a direct function in the human body, whereas the omega-3s in flax, known as ALA, do not. Instead, the ALA must be converted to EPA, and ultimately to DHA, before it can be put to use in our cell membranes. Since humans complete this conversion poorly (it’s estimated that between 0% to 9% of ALA is fully converted to DHA), it’s generally accepted that fish is a better choice than flax for heart health — at least when taken in the oil form.
Just to confuse things a little more, eating ground flaxseed for heart health actually does make good sense: In human studies, the addition of a daily dose of ground flaxseed can result in LDL, or “bad” cholesterol reductions of 9% to 18% for those with normal cholesterol levels, or 4% to 10% for those with high cholesterol. The key is in the semantics: While ground flaxseed contains soluble fibre, 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 a delicate creature, 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 yogourt.
PSYLLIUM: HEART HEALTH UNCOVERED
Oddball spelling aside (the “P” is silent), psyllium fibre is another soluble fibre that has a well-documented capacity to lower cholesterol. Derived from psyllium husks (which you can buy directly), psyllium fibre 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 fibre, 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 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% reduction in LDL cholesterol after four weeks on a psyllium-fibre cereal.
THE BOTTOM LINE
Adding soluble fibre to your diet, whether as oat bran, ground flaxseed or psyllium fibre or in other forms -- such as fruit, beans, barley or soybeans -- is a tried, tested and generally safe way to control your cholesterol. As with all types of fibre, however, too much can be a good thing: When increasing your intake, make sure to do so gradually and drink plenty of water to prevent excess gas, bloating or abdominal discomfort. Also, since some types of fibre, particularly psyllium fibre, can reduce absorption of certain medications, you should speak with your physician or pharmacist before starting a new supplement regimen.
- Jennifer Sygo is a dietitian in private practice at Cleveland Clinic Canada (clevelandclinic.ca), which offers executive physicals, prevention and and personal health care management in Toronto.
February is heart month, so we’ll be taking a closer look at the influence functional foods and supplements can have on heart health. This week, we’ll focus on different sources of soluble fibre, a type of fibre often recommended for controlling cholesterol levels.
OAT BRAN IS BACK
Readers who remember the 1980s well can probably recall the hoopla surrounding oat bran. After petering out for a decade or so, 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 fibre that can bind cholesterol in the digestive tract, causing you to excrete it 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 yogourt or in a smoothie. (Oat bran is also particularly rich in vitamin E, a difficult-to-get vitamin many Canadians miss in their diet). Another alternative is to choose a cold cereal that contains oat bran — General Mills’ Cheerios being one popular choice, for example.
FLAX: FOR BETTER OR WORSE?
In the past, I’ve recommended fish oil over flaxseed oil, especially for heart health. As the reasoning goes, both flax and fish contain essential omega-3 fatty acids, but the types of omega-3s in fish, known as DHA and EPA, have a direct function in the human body, whereas the omega-3s in flax, known as ALA, do not. Instead, the ALA must be converted to EPA, and ultimately to DHA, before it can be put to use in our cell membranes. Since humans complete this conversion poorly (it’s estimated that between 0% to 9% of ALA is fully converted to DHA), it’s generally accepted that fish is a better choice than flax for heart health — at least when taken in the oil form.
Just to confuse things a little more, eating ground flaxseed for heart health actually does make good sense: In human studies, the addition of a daily dose of ground flaxseed can result in LDL, or “bad” cholesterol reductions of 9% to 18% for those with normal cholesterol levels, or 4% to 10% for those with high cholesterol. The key is in the semantics: While ground flaxseed contains soluble fibre, 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 a delicate creature, 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 yogourt.
PSYLLIUM: HEART HEALTH UNCOVERED
Oddball spelling aside (the “P” is silent), psyllium fibre is another soluble fibre that has a well-documented capacity to lower cholesterol. Derived from psyllium husks (which you can buy directly), psyllium fibre 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 fibre, 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 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% reduction in LDL cholesterol after four weeks on a psyllium-fibre cereal.
THE BOTTOM LINE
Adding soluble fibre to your diet, whether as oat bran, ground flaxseed or psyllium fibre or in other forms -- such as fruit, beans, barley or soybeans -- is a tried, tested and generally safe way to control your cholesterol. As with all types of fibre, however, too much can be a good thing: When increasing your intake, make sure to do so gradually and drink plenty of water to prevent excess gas, bloating or abdominal discomfort. Also, since some types of fibre, particularly psyllium fibre, can reduce absorption of certain medications, you should speak with your physician or pharmacist before starting a new supplement regimen.
- Jennifer Sygo is a dietitian in private practice at Cleveland Clinic Canada (clevelandclinic.ca), which offers executive physicals, prevention and and personal health care management in Toronto.
