Unit 2 - Nutrition Therapy & Supplementation for Osteoporosis Flashcards
What does bone metabolism (AKA bone remodeling) play an important role in?
plays an important role in building and maintaining the skeletal system and teeth, which requires vitamins, minerals, and hormones working cooperatively to maintain healthy bones.
However, imbalances in bone metabolism can occur in some people who develop _______.
osteoporosis
What is bone remodeling & when does it occur?
The growth and maintenance of bones (bone remodeling) occurs when old bone tissues are resorbed/removed and replaced by new tissues, which is important for repair and reshaping of bones after fractures or micro cracks due to stress.
What is crucial for bone remodeling?
The interactions of several nutrients, calcium, phosphorous, magnesium and fluoride; vitamins, vitamins A, D, and C; and hormones, parathyroid hormone (PTH) and calcitonin, are crucial for bone remodeling.
The hormonal control of bone remodeling that take place at the genetic level, leads to…
the activation of signalling pathways in bone cells that affect their growth, survival, differentiation and functions.
What are the signalling pathways under investigation?
include the beta-catenin and receptor activator of nuclear factor kappa-beta ligand (RANKL)/ receptor activator of nuclear factor kappa beta (RANK) pathways
What are the 3 main types of bone cells?
- Osteoblasts
- Osteocytes
- Osteoclasts
Osteoblasts:
are bone formation cells that synthesize the protein collagen matrix and deposit minerals, including calcium and phosphorous/phosphate, into the protein matrix (calcification).
Osteocytes:
that represent most of the bone cells are matured osteoblasts, which are entrapped in the protein matrix that they produced. They send signals to osteoblasts to build new bone tissues in response to stress. For example, weight-bearing physical activity, which results in micro cracks.
Osteoclasts:
are bone-removing cells that secrete hydrochloric acid to dissolve the calcified minerals, and enzymes collagenase and acid phosphatase to lyse the bone protein matrix.
What is the hormonal control of bone metabolism?
Calcium and phosphorous are part of the bone structure. When there is decrease in blood calcium and phosphorous, they are mobilized from the bones into the blood. The blood concentrations of these minerals are under control of the parathyroid hormone (PTH), vitamin D, calcitonin, and other hormones.
What do the Parathyroid hormone (PTH), vitamin D, calcitonin, & other hormones play a major role in?
These hormones play a major role in the resorption, reabsorption, absorption, and excretion of calcium and phosphorous from the kidneys, bones, and intestine
Parathyroid hormone:
tends to increase calcium and phosphorous concentrations in the blood, by promoting the resorption of bones, synthesis of active vitamin D in the kidney, and reabsorption of calcium in the kidneys.
Vitamin D/calciferol:
is actually a hormone because it is not an essential nutrient from foods. Given enough sun, the body can synthesize vitamin D. Vitamin D stimulates the breakdown (resorption/mobilization) of bone tissues to release calcium and phosphate into the blood, absorption of calcium from the intestine, and reabsorption of calcium in the kidneys.
Calcitonin:
in contrast to vitamin D and PTH, tends to decrease the concentration of plasma calcium by reducing calcium uptake in the kidneys, and stimulating calcification (the deposition of calcium and other minerals) into the protein matrix of bone tissues.
Vitamin D, PTH, and calcitonin elicit their actions of affecting calcium and phosphate blood concentrations, by their effects on the bone cells:
- Parathyroid hormone (PTH)
- Vitamin D
- Calcitonin
Parathyroid hormone (PTH):
increases osteoclast activity.
Vitamin D:
increases osteoclast activity.
Calcitonin:
increases osteoblast and osteocyte activities.
In addition, _______, _______, & _________ inhibit osteoclast activity
- estrogen
- growth hormone
- testosterone
The effects of these hormones on the cells lead to bone remodeling
What can happen in postmenopausal women?
there is an increased risk of osteoporosis; women loose bone mass and are high risk of bone fractures. So do middle-aged and older men.
When do people develop osteoporosis?
People develop osteoporosis when their bone loss becomes extreme such that bone fractures occur under ordinary everyday stresses.
What is the prevalence of osteoporosis & what is it associated with?
It is more prevalent in women and is associated with increased mortality and morbidity due to complications from bone fractures.
Both _____ and _______ factors contribute to osteoporosis
- genetic
- environmental
The risk factors for osteoporosis include:
reduced peak bone mass and previous fractures, and others listed below.
These risk factors can be either non-modifiable or modifiable.
Non- modifiable factors include:
female gender, older age, small and thin body frame, ethnicity (Caucasian, Asian, Hispanic/Latino heritage, or African America Women), and family history of osteoporosis, estrogen and testosterone deficiency.
Modifiable risk factors include:
sedentary lifestyle (lack of physical exercise), nutritional risk factors (inadequate intake of minerals and vitamins essential for bone growth and maintenance), and lifestyle (tobacco use, alcohol abuse) and certain medications (glucocorticoids and anticonvulsants).
Apart from calcium, phosphorous, vitamin D, magnesium, fluoride, and vitamins K, C, and A are involved …
maintaining bone health
______ & __________ put stress on bones that are important in building new bone tissues
Physical activity and weight training
Except for vitamin D, we obtain _____ and ______ from animal and plant foods.
- calcium
- phosphorouos
What is the food group most associated with bone health?
calcium
- dairy group (milk & milk products)
What does the calcium group provide?
provides a rich source of calcium, between 20% and 75% of recommended calcium, protein, phosphorous, magnesium, and potassium
What foods are rich in calcium?
Vegetables including beet greens, green cabbage, broccoli, and turnip greens are good sources of available calcium. Collard greens, parsley, and watercress, and beans and almond are also rich in calcium. Some vegetables including spinach and Swiss chard although are calcium rich but provide very little, because they contain binders that prevent calcium absorption. Breakfast cereal, fruit juice, and mineral water are fortified with calcium.
What foods are rich in phosphorous?
Although milk and milk products are rich sources of phosphorous, animal protein (meat, poultry, and eggs) and fish are the best sources of phosphorous. Phosphorous is abundant in most foods. A balanced diet in calcium and protein has adequate amounts of phosphorous, because all three nutrients are present in the same foods.
What foods are rich in Vitamin D?
Exposure to sunlight can provide enough amount of vitamin D in our body. However, additional food sources are necessary in most cases to satisfy the recommended dietary allowance (RDA). Only a few animal foods (eggs, liver, and butter) and some fatty fish (salmon and sardines) contain a significant amount of vitamin D. Some foods including milk and margarine are good sources of fortified vitamin D.
Is there a cure for osteoporosis?
no
______ is an important component for treating individuals with osteoporosis.
Nutrition
____ may be the most crucial complement to drugs for combination therapy.
Diet
However, for individuals at risk of osteoporosis, the more important role of diet is prevention or slow disease progression.
Optimal protection of bone health partly depends on adequate intake of nutrients. The adequate intake of essential nutrients for bone health, and enough exposure to sunlight, is important at all stages of life
The key recommendation from Health Canada for the prevention of osteoporosis or slowing down bone loss is…
adequate dietary intake of calcium and vitamin D to obtain the RDA, which depends on age and sex (Table 2) amongst other factors.
Large prospective studies has shown that ______ deficiency is associated with severity of osteoporosis in elderly and postmenopausal women.
vitamin D
Vitamin D fortified foods have significant effect on…
increasing bone mineral density (BMD) and serum level of vitamin D and decreasing PTH levels in people with prior vitamin D deficiency.
However, vitamin D has no significant beneficial change on…
bone turn over markers (BTM).
The beneficial effects of vitamin D on fractures (reduction in lumbar spine, hip, and total body fractures) and on bone mineral content (BMC), depend on…
vitamin D deficiency status, ethnicity, sex, age, nutrient components of diet, and lifestyle choices.
In general, ______ can have a positive effect on bone density and health. However, the beneficial role of dairy products in preventing fractures is uncertain and controversial
dairy products
The reviews, meta-analysis, and current studies about the effects of different dietary patterns are consistent with the observations that the __________ is beneficial for bone status when compared to the Western diet (a control diet used in interventional trials).
Mediterranean diet
Vegetarian diets:
contain lower amounts of calcium, vitamin D, vitamin B12, protein and omega-3 fatty acids, all of which have important roles in maintaining bone health.
However, healthy vegetarian diets usually contain greater quantities of several protective bone-related nutrients such as…
magnesium, potassium, vitamin K, and antioxidant and anti-inflammatory phytonutrients.
Nevertheless, the limited amount of studies done so far suggest that ______ may be at higher risk of low BMD and fractures.
Vegans
Dietary patterns including fruit, vegetables, whole grains, poultry, fish, nuts and legumes, milk and dairy products will be beneficial for…
bone health, decreasing the risks of osteoporosis and fractures.
Why is getting calcium and vitamin D from foods better than dietary supplements?
Getting calcium and vitamin D from foods is better than dietary supplements because food offers fringe benefits of supplying substantial amounts of other nutrients, which can also enhance the absorption of both calcium and vitamin D.
Some people also absorb vitamin D and calcium better from ____ than _____
food than supplements.
Supplements are usually recommended when intake from food for calcium and vitamin D are ______
insufficient
Who should take calcium and vitamin D supplements?
Inclusion of calcium and vitamin D supplements to complement their dietary levels may be indicated for the following groups:
Patients who have inadequate intake of milk and milk products (including those who are lactose intolerant); older adults, >70 years of age, with limited sun exposure; post-menopausal women at higher risks of osteoporosis; infants and children up to three years with specific risk of osteoporosis; and pregnant women. Also, those following a vegan diet; are receiving long-term treatment with corticosteroids; and have certain bowel or digestive diseases that decrease their ability to absorb calcium, such as inflammatory bowel disease or celiac disease, may take calcium and vitamin D supplements.
The recommendations for calcium & vitamin D supplements should consider the _________, which is the maximum daily dose that is less likely to cause toxicity (Table 3), and the following specific instructions
Tolerable Upper Intake Level
Calcium supplements:
Several different kinds of calcium compounds are used in calcium supplements. Each compound contains varying amounts of elemental calcium. Common calcium supplements may be labeled as calcium carbonate (40% elemental calcium); calcium citrate (21% elemental calcium); calcium gluconate (9% elemental calcium); and calcium lactate (13% elemental calcium).
The two main forms of calcium supplements are _______ & ________
calcium carbonate and calcium citrate.
The doses should be based on the elemental calcium and not calcium salt:
Calcium carbonate should not be consumed with food, but calcium citrate supplements can be taken with or without food.
The doses should be divided into three parts, each 400-500 mg/dose, and taken to reach 1200- 1500 mg/day.
Vitamin D supplements:
Osteoporosis Canada recommends supplementation of 400 to 1000 IU of vitamin D daily for all healthy adults 19 to 50 years of age (including pregnant and breastfeeding women). Supplementation of 800 to 2000 IU of vitamin D daily is recommended for those over the age of 50 or younger adults at high risk (with osteoporosis, multiple fractures, or conditions that may affect vitamin D absorption). To achieve optimal vitamin D status, daily supplementation with more than 1000 IU (25 μg) may be required. Daily doses up to 2000 IU (50 μg) are safe and do not necessitate monitoring. For individuals receiving pharmacologic therapy for osteoporosis, measurement of serum 25-hydroxyvitamin D should follow three to four months of adequate supplementation and should not be repeated if an optimal level (≥ 75 nmol/L) is achieved. Vitamin D3 (cholecalciferol) is the preferred supplement as it is better absorbed than vitamin D2.
Effectiveness of Calcium Supplements:
- Calcium supplements does produce a small positive effect on BMD in populations or
patients with a lower calcium dietary intake. - Calcium supplements alone does not reduce the risk of bone fractures.
- When treating osteoporosis, co-administration of calcium with anti-resorptive drugs has
not been shown to impact on treatment efficacy.
Effectiveness of Vitamin D Supplements:
- Vitamin D supplements does not improve BMD in clinical trials, except in subgroups with very low baseline levels of 25-hydroxyvitamin D.
- Correction of severe vitamin D deficiency (<25 nmol/L) with vitamin D supplements is necessary before use of potent anti-resorptive drugs to avoid hypocalcemia.
- Vitamin D supplements does slightly prevent fractures in populations with deficiency in vitamin D.
Effectiveness of Combined Calcium and Vitamin D Supplementation:
- Calcium in combination with vitamin D supplementation has a positive effect on BMD.
- Calcium and vitamin D combined supplementation have been associated with only weak
efficacy in reducing the risk of bone fractures in populations with already low calcium
dietary intake. - Supplementation with calcium and vitamin D does not prevent fractures in the general
population.
What are the harmful effects of Calcium?
- Excessive amounts or long-term use of calcium and vitamin D supplements can also cause calcium toxicity.
- Several studies and reviews have observed that long-term intake of calcium supplements commonly caused mild gastrointestinal side effects, particularly constipation, vomiting and nausea.
- Taking both calcium and vitamin supplements together does increase the risk of kidney stones.
- There is concern of potential adverse cardiovascular effects from calcium supplementation.
- Some calcium supplements can also interfere with iron and zinc absorption. For example, calcium carbonate can interfere with iron absorption from iron supplements. However, calcium citrate does not interfere with absorption of iron from iron supplements.
Some calcium supplements can also interfere with iron and zinc absorption:
For example, calcium carbonate can interfere with iron absorption from iron supplements. However, calcium citrate does not interfere with absorption of iron from iron supplements.
What are the harmful effects of Vitamin D?
Vitamin D is the vitamin most likely to have toxic effects when consumed in excess or after long-term usage.
Vitamin D supplementation:
Raises the concentrations of blood calcium, which tends to precipitate in soft tissues and forms stones, especially in the kidneys; causes calcification in blood vessels in the major arteries of the brain, heart, and lungs where it can cause death. Excess vitamin D intake can cause mild constipation, dizziness, and mental confusion, and can enhance bone resorption.
In review of the current scientific evidence, it is reasonable to conclude that:
- Taken together, current evidence does not support beneficial effects of calcium supplements, vitamin D supplements, or calcium with vitamin D supplementation in the
general population. - Calcium supplements with or without vitamin D supplementation, at the very best, provide a very small effect of decreasing the risk of fractures osteoporotic patients.
- The issues of poor long-term compliance of calcium supplementation is related to mild
but common gastrointestinal side effects - Calcium and vitamin D supplements, or in combination, do not reduce the risk of fractures in healthy women and men in the general population without deficiency of either nutrients.
