Dan Murray04.01.02
Most people are familiar with B vitamins as a group. Some even read labels and recognize niacin or its cousin niacinamide as a common food ingredient or as a part of their multivitamin. Beyond that however, niacin doesn't receive the amount of attention its vitamin counterparts do. As a nutrient, niacin is considered essential but as a nutritional approach to cholesterol management it may be the most under appreciated ingredient available. How can this common food/supplement ingredient consumed everyday be good for the heart? The scientific evidence should speak for itself.
Niacin is the shortened name for nicotinic acid and it is essential for normal physiological growth and maintenance. Niacin and niacinamide are collectively referred to as nicotinates and within the complex of B vitamins they are referred to as B3. Niacin and niacinamide are both white, odorless, crystalline powders that easily dissolve in water and they are quite stable when subjected to heat, light and moisture. Niacin and niacinamide play an important role in protein, energy and fat metabolism. The most common manifestation of a nicotinate deficiency is pellagra, which is a disease characterized by dermatitis, diarrhea and dementia.
As food and dietary supplement ingredients, nicotinates are functionally interchangeable, however, in pharmacological use niacin alone has stepped up to play a role in treating nerve disorders and improving abnormal blood cholesterol profiles. Traditionally niacin is used to enrich food products such as milled flour, rice and ready-to-eat cereal. Niacinamide is more often used in supplements and multivitamins. Both forms of vitamin B3 enjoy a long history of safety and efficacy.
Physiologically, niacin is easily and efficiently absorbed in supplement levels of 30-100 mg/day as well as pharmacological levels of 1-3 grams/day. Niacin is converted in vivo into nicotinamide. Nicotinamide is then absorbed into tissues and converted into two important coenzymes, nicotinamide adenine dinucleotide (NAD) and nicotinamide adenine dinucleotide phosphate (NADP). These coenzymes are prevalent throughout the body and are critical components in a series of reactions involving carbohydrate, protein and fat metabolism. As a water soluble B vitamin, niacin is generally not stored like the fat soluble vitamins A, D, E and K, so toxicity is rarely an issue in nutritional supplementation.
Studies indicate niacin can be synthesized in our bodies from the amino acid tryptophan1. However, scientists contend that the conversion of tryptophan to niacin could only occur after protein requirements were met2. Considering the low levels of tryptophan in most foods, a niacin dietary supplement is a far more efficient alternative.
Niacin happens to be one of those essential vitamins often included in the ingredient list of staple foods such as breads and cereals. While it is commonly found in grains and oilseeds, enrichment is necessary because much of the naturally occurring nicotinic acid is chemically bound and not available for absorption and utilization3. Animal feeds have been supplemented with niacin for decades for this very reason. Some of the best sources of available niacin are meat proteins and fish. Due to the importance and positive cost benefit relationship, niacin long ago carved out a niche in food fortification.
Much of our cardiovascular health knowledge has come from research conducted within the past 30 to 40 years. One significant long-term project, the Framingham Heart Study, made several declarations that detail the relationship between cholesterol and heart health. Cholesterol and triglycerides are part of a person's blood lipid profile. total cholesterol (TC) is primarily made up of low density lipoprotein (LDL), the "bad cholesterol and HDL (high density lipoprotein), the "good cholesterol."
In 1977, Framingham researchers described the effects of LDL, HDL and triglycerides. Excess amounts of LDL and triglycerides travel through the blood stream and are gradually deposited on the walls of arteries. Eventually a build up of these fat components (plaque), narrow the arteries and restrict blood flow to the heart. These fat deposits are considered contributing factors to Coronary Heart Disease (CHD), which is currently the leading cause of death in the U.S. among men and women.
Most people recognize that high cholesterol is unhealthy and should be monitored or treated by a physician. However, Framingham researchers in 1988 described how high levels of HDL were actually beneficial to reducing the risk of CHD. HDL is considered good cholesterol because it removes plaque, reducing the effects of LDL. Researchers at the Mayo clinic were discussing cholesterol fractions in the 1950s but the negative effects of LDL dominated most cholesterol research and discussion until recently4.
In 1993 the National Cholesterol Education Program (NCEP), an offshoot of the National Institute of Health (NIH), released cholesterol guidelines, which included HDL as part of the TC picture. In 1999, the NCEP reviewed the 1993 guidelines and issued new ones. The updated guidelines determined TC levels under 200 mg/dL to be desirable; levels between 200-239 mg/dL to be borderline high and TC levels above 239 mg/dL to be very high and a risk factor for CHD. In terms of LDL, NCEP determined levels between 130-159 mg/dL to be borderline high and LDL levels of 160 mg/dL and above to be high. For HDL, levels below 40 mg/dL were considered low and levels above 60 mg/dL were considered high. Consequently, high HDL levels can actually offset other risk factors and a low HDL may place an individual at greater risk than a borderline high LDL.
Niacin has quietly gained significant recognition for its therapeutic effects on improving blood cholesterol and triglyceride profiles. It was first recognized for its effect on cholesterol profiles from proceedings of the Mayo clinic in 19564. Considering its has been used therapeutically since the mid 1950s with literally dozens of human studies behind it, niacin has survived the test of time.
Niacin is unique because it plays a dual role, reducing LDL and increasing HDL. There are many products that reduce LDL but for people who exhibit low HDL, the treatment options to raise such levels are sparse. Niacin has been shown to be effective in monotherapy or in combination with statins, resins or fibrates. In monotherapy it has consistently shown double digit increases in HDL, in some cases by as much as 45%5. Decreases in LDL were also demonstrated in monotherapy by as much as 54%6. When used in combination with statins, niacin demonstrated additional double digit improvements in HDL and decreases in LDL6,7,8,9. Oddly, niacinamide offers no benefit in the management of blood lipids.
There are several theories on niacin's mode of action but no firm conclusions. One theory involves the inhibition of very low-density lipoprotein (VLDL), which is converted into LDL and triglycerides. A second theory is that niacin reduces the non-esterified or free fatty acids and triglycerides in the blood by inhibiting the breakdown of fat in tissues. Another idea is that niacin stimulates bile flow (in combination with resins), which may suppress cholesterol synthesis in the liver.
Niacin occasionally causes flushing (the physical sensation of warmth, tingling and redness of the skin caused by vasodilation) when individuals first begin supplementation. Flushing is very rare at levels found in most multivitamins but is more common at higher supplementation levels. A person starting on 500 mg-1 gram of plain niacin per day (not time-release) may experience this sensation in the first several days of supplementation.
The good news is that flushing poses no danger and the feeling passes completely in approximately 30 minutes. The intensity of flushing varies for individuals but most that adhere to a routine will experience almost no flushing after the first week of niacin supplementation. To offset the intensity of flushing, some people take a plain adult strength aspirin (325 mg) or a child's aspirin (81 mg) each day until the flushing passes.
Niacinamide is often used in dietary supplements and multivitamins because it is not associated with flushing. It is an excellent source of nicotinamide but it has no effect in managing blood cholesterol fractions and it does not play a role in heart health.
Niacin is an essential nutrient required for healthy growth and normal physiological maintenance and it plays an important role in protein, carbohydrate and fat metabolism. In dietary supplements, niacin and niacinamide are for the most part equivalent but only niacin shows powerful pharmacological effects in the treatment of unhealthy cholesterol and triglyceride profiles. Niacin has consistently demonstrated in studies that it can increase HDL and lower LDL and triglycerides, contributing to heart health.
Abnormal blood cholesterol levels have been identified as a contributing factor to cardiovascular heart disease, the leading cause of death in America10. Niacin is a safe and cost effective ingredient for dietary supplements to help manage blood lipid profiles. However, it is very important to consult with a physician about how niacin may offer an alternative nutritional approach to improve cholesterol and triglyceride levels.NW
About the author: Dan Murray is associate director of technical development-Nutrition at Lonza, Inc., Fair Lawn, NJ. He can be reached at 678-445-3535, Fax: 678-445-3611; E-mail: dmurray2@lonza-us.com.
References
1. Hederson, L.M. and C.J. Gross (1979). "Metbolism of niacin and niacinamide in perfused rat intestine." J. Nutrition 109:654
2. Kodicek, E. D.R. Ashby, M. Muller and C.J. Carpenter (1974). "The conversion of bound nicotinic acid to free nicotinamide on roasting sweetcorn." Proc. Nutr. Soc. 33:105A
3. Manoukas, A.G., R.C. Ringrose and A.E. Toori (1968). "Availability of niacin in corn, soybeanmeal and wheat middlings for the hen." Poultry Science 47:1836
4. Parson WB Jr (1998) Cholesterol Control Without Diet! The Niacin Solution, Lilac Press Scottsdale.
5. Martin-Jadraque R, Tatp F, Mostaza JM, Vega GL, Grundy SN(1996). Arch. Intern. Med. May 27; 156 (10) : 1081-8
6. Brown, BG, Bardsley J, Poulin D, Hillger LA, Dowdy A, Maher VM, Zhoa XQ, Albers JJ, Knopp RH (1997). "Moderate dose, three drug therapy with niacin, lovastatin, and colestipol to reduce low-density lipoprotein cholesterol to less than 100mg/dl in patients with hyperlipidemia and coronary artery disease." Am J Cardiol 80; 111-5
7. Luria MH, Sapoznikov D Postgrad Med J (1993) Apr; 60 (810): 296-9 Raising HDL cholesterol with low-dose nicotinic acid and bezafibrate; preliminary experience.
8. Cashin-Hemphill L, Mack WJ, Pogoda JM, Sanmarco ME, Azen SP, Blankenhorn. "Beneficial effects of colestipol-niacin in coronary artherosclerosis. A four-year follow-up study. (resins)." JAMA (1990) Dec 19; 264 (23) ; 3013-7
9. Vega, G.L. and M.D. Grundy (1994) "Lipoprotein responses to treatment with Lovistatin, gemfibrozil and nicotinic acid in normolipidemic patients with hypoalphalipoproteinemia." Arch. Int. Med. 154:73-82.
10. American Heart Assc.Website 2001-2 (www.americanheart.org)
What is Niacin?
Niacin is the shortened name for nicotinic acid and it is essential for normal physiological growth and maintenance. Niacin and niacinamide are collectively referred to as nicotinates and within the complex of B vitamins they are referred to as B3. Niacin and niacinamide are both white, odorless, crystalline powders that easily dissolve in water and they are quite stable when subjected to heat, light and moisture. Niacin and niacinamide play an important role in protein, energy and fat metabolism. The most common manifestation of a nicotinate deficiency is pellagra, which is a disease characterized by dermatitis, diarrhea and dementia.
As food and dietary supplement ingredients, nicotinates are functionally interchangeable, however, in pharmacological use niacin alone has stepped up to play a role in treating nerve disorders and improving abnormal blood cholesterol profiles. Traditionally niacin is used to enrich food products such as milled flour, rice and ready-to-eat cereal. Niacinamide is more often used in supplements and multivitamins. Both forms of vitamin B3 enjoy a long history of safety and efficacy.
Physiologically, niacin is easily and efficiently absorbed in supplement levels of 30-100 mg/day as well as pharmacological levels of 1-3 grams/day. Niacin is converted in vivo into nicotinamide. Nicotinamide is then absorbed into tissues and converted into two important coenzymes, nicotinamide adenine dinucleotide (NAD) and nicotinamide adenine dinucleotide phosphate (NADP). These coenzymes are prevalent throughout the body and are critical components in a series of reactions involving carbohydrate, protein and fat metabolism. As a water soluble B vitamin, niacin is generally not stored like the fat soluble vitamins A, D, E and K, so toxicity is rarely an issue in nutritional supplementation.
Studies indicate niacin can be synthesized in our bodies from the amino acid tryptophan1. However, scientists contend that the conversion of tryptophan to niacin could only occur after protein requirements were met2. Considering the low levels of tryptophan in most foods, a niacin dietary supplement is a far more efficient alternative.
Niacin happens to be one of those essential vitamins often included in the ingredient list of staple foods such as breads and cereals. While it is commonly found in grains and oilseeds, enrichment is necessary because much of the naturally occurring nicotinic acid is chemically bound and not available for absorption and utilization3. Animal feeds have been supplemented with niacin for decades for this very reason. Some of the best sources of available niacin are meat proteins and fish. Due to the importance and positive cost benefit relationship, niacin long ago carved out a niche in food fortification.
A Cholesterol Primer
Much of our cardiovascular health knowledge has come from research conducted within the past 30 to 40 years. One significant long-term project, the Framingham Heart Study, made several declarations that detail the relationship between cholesterol and heart health. Cholesterol and triglycerides are part of a person's blood lipid profile. total cholesterol (TC) is primarily made up of low density lipoprotein (LDL), the "bad cholesterol and HDL (high density lipoprotein), the "good cholesterol."
In 1977, Framingham researchers described the effects of LDL, HDL and triglycerides. Excess amounts of LDL and triglycerides travel through the blood stream and are gradually deposited on the walls of arteries. Eventually a build up of these fat components (plaque), narrow the arteries and restrict blood flow to the heart. These fat deposits are considered contributing factors to Coronary Heart Disease (CHD), which is currently the leading cause of death in the U.S. among men and women.
Most people recognize that high cholesterol is unhealthy and should be monitored or treated by a physician. However, Framingham researchers in 1988 described how high levels of HDL were actually beneficial to reducing the risk of CHD. HDL is considered good cholesterol because it removes plaque, reducing the effects of LDL. Researchers at the Mayo clinic were discussing cholesterol fractions in the 1950s but the negative effects of LDL dominated most cholesterol research and discussion until recently4.
In 1993 the National Cholesterol Education Program (NCEP), an offshoot of the National Institute of Health (NIH), released cholesterol guidelines, which included HDL as part of the TC picture. In 1999, the NCEP reviewed the 1993 guidelines and issued new ones. The updated guidelines determined TC levels under 200 mg/dL to be desirable; levels between 200-239 mg/dL to be borderline high and TC levels above 239 mg/dL to be very high and a risk factor for CHD. In terms of LDL, NCEP determined levels between 130-159 mg/dL to be borderline high and LDL levels of 160 mg/dL and above to be high. For HDL, levels below 40 mg/dL were considered low and levels above 60 mg/dL were considered high. Consequently, high HDL levels can actually offset other risk factors and a low HDL may place an individual at greater risk than a borderline high LDL.
Niacin's Role in Creating a Healthy Cholesterol Profile
Niacin has quietly gained significant recognition for its therapeutic effects on improving blood cholesterol and triglyceride profiles. It was first recognized for its effect on cholesterol profiles from proceedings of the Mayo clinic in 19564. Considering its has been used therapeutically since the mid 1950s with literally dozens of human studies behind it, niacin has survived the test of time.
Niacin is unique because it plays a dual role, reducing LDL and increasing HDL. There are many products that reduce LDL but for people who exhibit low HDL, the treatment options to raise such levels are sparse. Niacin has been shown to be effective in monotherapy or in combination with statins, resins or fibrates. In monotherapy it has consistently shown double digit increases in HDL, in some cases by as much as 45%5. Decreases in LDL were also demonstrated in monotherapy by as much as 54%6. When used in combination with statins, niacin demonstrated additional double digit improvements in HDL and decreases in LDL6,7,8,9. Oddly, niacinamide offers no benefit in the management of blood lipids.
There are several theories on niacin's mode of action but no firm conclusions. One theory involves the inhibition of very low-density lipoprotein (VLDL), which is converted into LDL and triglycerides. A second theory is that niacin reduces the non-esterified or free fatty acids and triglycerides in the blood by inhibiting the breakdown of fat in tissues. Another idea is that niacin stimulates bile flow (in combination with resins), which may suppress cholesterol synthesis in the liver.
Niacin and Flushing
Niacin occasionally causes flushing (the physical sensation of warmth, tingling and redness of the skin caused by vasodilation) when individuals first begin supplementation. Flushing is very rare at levels found in most multivitamins but is more common at higher supplementation levels. A person starting on 500 mg-1 gram of plain niacin per day (not time-release) may experience this sensation in the first several days of supplementation.
The good news is that flushing poses no danger and the feeling passes completely in approximately 30 minutes. The intensity of flushing varies for individuals but most that adhere to a routine will experience almost no flushing after the first week of niacin supplementation. To offset the intensity of flushing, some people take a plain adult strength aspirin (325 mg) or a child's aspirin (81 mg) each day until the flushing passes.
Niacinamide is often used in dietary supplements and multivitamins because it is not associated with flushing. It is an excellent source of nicotinamide but it has no effect in managing blood cholesterol fractions and it does not play a role in heart health.
Conclusion
Niacin is an essential nutrient required for healthy growth and normal physiological maintenance and it plays an important role in protein, carbohydrate and fat metabolism. In dietary supplements, niacin and niacinamide are for the most part equivalent but only niacin shows powerful pharmacological effects in the treatment of unhealthy cholesterol and triglyceride profiles. Niacin has consistently demonstrated in studies that it can increase HDL and lower LDL and triglycerides, contributing to heart health.
Abnormal blood cholesterol levels have been identified as a contributing factor to cardiovascular heart disease, the leading cause of death in America10. Niacin is a safe and cost effective ingredient for dietary supplements to help manage blood lipid profiles. However, it is very important to consult with a physician about how niacin may offer an alternative nutritional approach to improve cholesterol and triglyceride levels.NW
About the author: Dan Murray is associate director of technical development-Nutrition at Lonza, Inc., Fair Lawn, NJ. He can be reached at 678-445-3535, Fax: 678-445-3611; E-mail: dmurray2@lonza-us.com.
References
1. Hederson, L.M. and C.J. Gross (1979). "Metbolism of niacin and niacinamide in perfused rat intestine." J. Nutrition 109:654
2. Kodicek, E. D.R. Ashby, M. Muller and C.J. Carpenter (1974). "The conversion of bound nicotinic acid to free nicotinamide on roasting sweetcorn." Proc. Nutr. Soc. 33:105A
3. Manoukas, A.G., R.C. Ringrose and A.E. Toori (1968). "Availability of niacin in corn, soybeanmeal and wheat middlings for the hen." Poultry Science 47:1836
4. Parson WB Jr (1998) Cholesterol Control Without Diet! The Niacin Solution, Lilac Press Scottsdale.
5. Martin-Jadraque R, Tatp F, Mostaza JM, Vega GL, Grundy SN(1996). Arch. Intern. Med. May 27; 156 (10) : 1081-8
6. Brown, BG, Bardsley J, Poulin D, Hillger LA, Dowdy A, Maher VM, Zhoa XQ, Albers JJ, Knopp RH (1997). "Moderate dose, three drug therapy with niacin, lovastatin, and colestipol to reduce low-density lipoprotein cholesterol to less than 100mg/dl in patients with hyperlipidemia and coronary artery disease." Am J Cardiol 80; 111-5
7. Luria MH, Sapoznikov D Postgrad Med J (1993) Apr; 60 (810): 296-9 Raising HDL cholesterol with low-dose nicotinic acid and bezafibrate; preliminary experience.
8. Cashin-Hemphill L, Mack WJ, Pogoda JM, Sanmarco ME, Azen SP, Blankenhorn. "Beneficial effects of colestipol-niacin in coronary artherosclerosis. A four-year follow-up study. (resins)." JAMA (1990) Dec 19; 264 (23) ; 3013-7
9. Vega, G.L. and M.D. Grundy (1994) "Lipoprotein responses to treatment with Lovistatin, gemfibrozil and nicotinic acid in normolipidemic patients with hypoalphalipoproteinemia." Arch. Int. Med. 154:73-82.
10. American Heart Assc.Website 2001-2 (www.americanheart.org)
