vitamin b3 (niacin)

VITAMIN B3

STRUCTURE OF VITAMIN B3

Molecular structure

Can be describes as

1. Nicotinamide 2. Nicotinic acid

Coenzyme form of niacin

FOOD SOURCE AND RECOMMENDATION

FOOD SOURCE AND RECOMMENDATION

• ●RNI Malaysia recommended: •Men: 16 mg NE/day.•Women: 14 mg NE/day.

•Pregnant women: 18 mg NE/day.•Lactating women: 17 mg NE/day.• ● Both cooked and raw foods provide

vitamin B3, which does not break down with heating.

•●Can leach into cooking water.

• ●Diverse types of healthy foods naturally contain vitamin B3; others are fortified with B3 during processing.

FOOD SOURCE AND RECOMMENDATION

FOOD EXPLANATION

FISH -Baked tuna tops the list ( 18.7 milligrams of vitamin B3 per 3-ounce serving) -Canned tuna packed in water is a healthy alternative, providing 11.3 milligrams of niacin per 3-ounce serving. -Others: salmon, swordfish, halibut and rainbow trout

WHOLE GRAIN CEREALS AND BREAD

-ready-to-eat cereals and bread provide much of the vitamin B3 in the average diet-Three-quarters of a cup of wheat, corn or whole-grain breakfast flakes contains approximately 8 to 20 milligrams of vitamin B3 (depends on brand)

LEAN MEAT -provide approximately 6 to 12 milligrams of niacin per 3-ounce serving-baked, skinless chicken breast; roasted, light meat turkey; broiled top sirloin beef; and roasted pork or lamb loin.

VEGETABLES AND NUTS -Potatoes, corn and green or black-eyed peas boost the vitamin B3 content of a meal by roughly 2 to 3 milligrams per 1-cup serving-Dry-roasted peanuts are a healthy, nutritious snack and provide 3.8 milligrams of vitamin B3 per ounce.

DEFICIENCY OF VITAMIN B3

• Vitamin B3 or niacin deficiency due to malabsorption is common in celiac disease before gluten is removed from the diet.

• Niacin deficit can be aggravated by a lack of niacin or the amino acid tryptophan in the diet.

• Our body uses tryptophan to make niacin as a back up mechanism.

Deficiency Symptoms

High Cholesterol• High cholesterol may just be the result of a bad diet

vitamin B3, or niacin.• Vitamin B3 is responsible for maintaining the cholesterol

levels. • Vitamin B3 can lowers our cholesterol by fighting against

bad cholesterol and raising the levels of good cholesterol in our body.

• By doing this , arteries do not get clogged up by bad cholesterol and have a lower chance of suffering from heart disease.

• When we get the vitamin B3 deficiency, the body cannot produce more good cholesterol and can get a high levels on bad cholesterol in our blood.

Problems with metabolism: muscle weakness, lack of energy, weight loss, decreased tolerance to cold.

Problems with the nervous system: irritability, dizziness, fatigue, poor concentration, poor memory, anxiety, apathy, depression, headache, neuritis (numbness, burning in various parts), tremors, restlessness and hyperactivity in children.

Problems in the digestive tract: anorexia, distorted taste, indigestion, scarlet colored tongue, burning of the mouth, throat, and esophagus, abdominal discomfort and distention, nausea, diarrhea or constipation.

Problems with the skin and mucous membranes: sensitivity of skin exposed to sunlight causing a red, itchy, scaly rash that resembles mild sunburn, and inflammation of mucous membranes of vagina and urethra.

DISEASE

PELLAGRA• A disease characterised by diarrhoea, dermatitis and dementia. If left

untreated, death is the usual outcome.

Diarrhea can be bloody and other digestive disturbances worsen with vomiting.

Dermatitis develops symmetrically in areas exposed to sunlight with hyperpigmentation (dark color), thickening and cracking of the skin, itchy red wet areas from chafing, and “necklace” sores on the lower neck. Subcutaneous fibrosis and scarring within the skin may be seen in late stages. A bright red swollen tongue which in chronic stage is fissured and is similar to raw meat. Inflammation of other mucous membranes worsens with increasing deficit.

Dementia is due to neuronal loss (death of nerve cells) with development of amnesia, disorientation, confabulation, and delirium.

Death ensues eventually if the niacin deficiency is left untreated such as dermatitis and dementia.

• Pellagra can occur in 2 ways:Primary pellagra: results from inadequate niacin and/or

tryptophan in the diet (mainly in developing countries or poverty stricken areas).

Secondary pellagra: occurs when there is enough niacin in the diet but something prevents its absorption and processing. Causes of secondary pellagra include:• Chronic alcoholism• Prolonged diarrhoea• Gastrointestinal diseases such as ulcerative colitis• Liver cirrhosis• Carcinoid tumours• Hartnup disease (tryptophan metabolism disorder)• Drugs e.g. isoniazid, azathioprine

Toxicity of Vitamin B3

Toxicity• Dosage >3000 mg per day cause severe toxicity which

affect multiple system in body• cause severe digestive complications including

vomiting, cramping and diarrhea• Cause flushing or reddening skin• Side effect :

Agitation Headache

Anxiety Heart palpitations

Blurred vision Jaundice : skin yellowing

Breathing difficulty Liver damage

Diarrhoea Nausea

Dizziness Panic attack

Dietary Reference Intake

• Infants • Infants birth – 6 months : 2mg/day (adequate intake)• Infants 7 months – 1 years : 4mg/day (adequate intake)

• Children • Children 1 – 3 years : 6 mg/day (RDA)• Children 4 - 8 years : 8 mg/day (RDA)• Children 9 – 13 years : 12 mg/day (RDA)

Dietary Reference Intake• Adolescents and Adults• Males age 14 and older : 16mg/day• Females age 14 and older : 14mg/day• Pregnant women : 18 mg/day (RDA)• Breastfeeding women : 17 mg/day (RDA)

Precautions

• People with a history of liver disease, kidney disease, or stomach ulcers should not take niacin supplements

• Stop taking niacin or niacinamide at least two weeks before a scheduled surgery

• Niacin and niacinamide may make allergies worse by increasing histamine.

• People with low blood pressure should not take niacin or niacinamide because they may cause a dangerous drop in blood pressure.

• People with coronary artery disease or unstable angina should not take niacin, as large doses can raise the risk of heart rhythm problems.

Niacin Use and Cutaneous Flushing: Mechanismsand Strategies for Prevention

INTRODUCTION• Form of vitamin B3.• water-soluble B-complex vitamins. • a potent lipid-modifying agent with broad-

spectrum effects.• reduces low-density lipoprotein cholesterol,

triglyceride, and lipoprotein(a) levels. • increasing high-density lipoprotein cholesterol.

MECHANISM OF FLUSHING• Activation of the G protein– coupled

receptor GPR109A can produce differential responses depending on the location of the receptor. It has been suggested that when nicotinic acid activates GPR109A on adipocytes, the resultant antilipolytic effects contribute to the highly desirable normalization of lipoprotein profiles.

• However, when nicotinic acid activates GPR109A on dermal dendritic cells (DC) or dermal macrophages, the subsequent mobilization of arachidonic acid and its conversion to vasodilatory prostaglandins result in the characteristic flushing response.

• Because GPR109A expression extends beyond adipose and immune cells located in the skin (eg, spleen, lymphoid cells, lung), it is likely that the activation of GPR109A in these cells and tissues may also contribute to the clinical efficacy of nicotinic acid.

Relation of Niacin Dose to Flushing• onset of flushing : 20 minutes to 1hour after niacin dosing.• duration : 1 hour.• Niacin dosing has been found to be associated with

vasodilation-induced flushing.• Available in 3 formulations, including immediate-release,

ER, and long-acting niacin. Each differs with respect to safety and efficacy profiles, with long-acting niacin having less of a flushing effect, although its metabolism can increase the risk for hepatotoxic effects.

• 50 to 500-mg tablets or capsules. • Initial recommended therapeutic daily dose : 100 mg 3

times a day.• maximum daily dose : 1,000 mg.

Effect of the extended-release (ER) formulation of niacin on flushing

Impact of aspirin administration on niacin-associated flushing. ER extended-release; VAS visual analogue scale.

Reductions in niacin-associate flushing with aspirin (ASA) and ibuprofen (IBU). VAS visual analogue scale. *p < 0.05 vs placebo, †p <0.05 vs ibuprofen.

Strategies for improving adherence and managing flushing with niacin:

● Long-term adherence with niacin is dependent on patient awareness and education.

● Patients should be instructed to avoid interrupting therapy with niacin whenever possible.

● Initiate therapy using small doses, taken with meals, and then slowly titrate upward over several weeks to achieve treatment goals.

● Advise patients to take an adult aspirin or other nonsteroidal anti-inflammatory agent 30 minutes before dose.

● Recommend that patients avoid spicy foods and hot or alcoholic beverages near dose.

● Use extended-release instead of intermittent-release niacin to minimize adverse effects and enhance adherence.

CONCLUSIONS

• Because niacin has recognized cardiovascular benefits, promoting patient awareness of factors that can minimize niacin-induced flushing can help enhance the tolerability of this valuable dyslipidemic agent. Niacin is an attractive option for treating dyslipidemic patients, and tolerance to niacin-induced flushing develops rapidly. Healthcare professionals should particularly address flushing during niacin dose titration.