26
September
2007
Trans Fatty Acids are talked about a lot because it is associated with a higher risk of cardiovascular disease. What are they? Organic chemistry means carbon has to be involved because it is the base of the molecule, such as fatty acids. Fatty acids consist of a string of carbons (like a string of pearls) with oxygen and hydrogen towards the end of the chain. If the fatty acid is saturated, that means the carbons’ free bonding sites are all bonded to hydrogen atoms (saturated with hydrogens). In general saturated fats are not healthy for you. Unsaturated fatty acids mean some of the carbon atoms double bond to each other – and therefore let go of some hydrogen atoms (so not saturated with hydrogen atoms). When two carbon atoms are double bonded, there are 2 formations possible: cis and trans. Cis means in the 2 carbons that are double bonded, their 1 remaining hydrogen atoms are on the same side of the chain. Trans means in the 2 carbons that are double bonded, their 1 remaining hydrogen atoms are on the opposite sides of the chain.
Saturated fats are linked to heart disease. Cis fats are unsaturated and tend to be a healthy type of fat. However, Trans fatty acids are considered to be worse than saturated fats because of it appears to increase the risk coronary heart disease (CHD) events, such as heart attacks. Trans fats are called partially hydrogenated oils because once there were 2 double bonded carbons, and it was changed to only 1 double carbon – so the other double bonded carbon because single bonded and 2 hydrogen were added (i.e. hydrogenated)
Saturated fats have no health benefits, so why are they used? Taste and the palatable nature of it, that is why. Trans fats are stable in fried cooking, and they have a long shelf life. They are often used in deep-fried fast foods, margarine, baked goods, packaged snacks, crackers, though naturally found as well in meat and dairy. Such fun foods that have a high percentage of trans fats include: French fries, breaded fish burgers, breaded chicken nuggets, enchildas, pies, danishes, doughnuts.
Americans average 2-3% of total calories to trans fatty acids, which is about 2-7grams a day. It appears if trans fats are virtually eliminated from the American diet and replaced by cis fatty acids, CHD events would be reduced by 22%.
There aren’t any randomized clinical trials because it would be unethical to study this since there is enough evidence to show trans fatty acids increases CHD events. How does CHD go up? Lipids are negatively affected by trans fats, so good cholesterol HDL goes down, bad cholesterol LDL goes up and becomes more dense, and triglycerides worsen. Lpa and B-100, lipoproteins which are kind of like subcholesterol particles, both increase as well with trans fats. Inflammatory chemicals in the body increase with trans fats, such as TNF, C-RP, IL-6, which are associated with atherosclerosis, cardiac sudden death, diabetes, and congestive heart failure.
One meta-analysis showed with only a 2% increase in trans fat to the diet was associated with a 23% increased risk of CHD. 23% isn’t that much, but considering only a 2% increase in consumption of trans fat, it spells “unhealthy”. Dieticians note there is no benefit to trans fat, so without any benefits, the risks are not worth it.
Denmark showed in 2004 that making the food industry lower the trans fatty acids did not significantly change the quality, cost, or availability of food. Also saturated fats were not used more to replace the trans fatty acids.
drjohnhong 
food, weight, cardiovascular 
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22
August
2007
Vitamin D deficiency is more prevalent than ever, probably because we don’t get enough sunlight. But with Mr. Ozone disappearing like characters on Lost, we are intentionally avoiding the sun to prevent skin cancer. Vitamin D isn’t really in a lot of foods, so ultraviolet B radiation is/was a major way to convert 7-dehydrocholesterol to previtamin D3 (it takes a series of step for the body to make active vitamin D which is called 1,25-dihydroxyvitamin D). It is estimated 1 billion people have either vitamin D deficiency or insufficiency, in particular those who live in northern climates. More than half women who are past menopause, osteoporotic, and on meds for bones are vitamin D deficient. Nearly half kids and younger adults have vitamin D deficiency by the end of winter.
Vitamin D is necessary for healthy bones, and it seems for many other organs. The body absorbs calcium and phosphorus in the gut much better with assistance of vitamin D. Also if vitamin D gets low, parathyroid hormone rises and that can thin out the bones.
25-hydroxy vitamin D is what is measured to see a person’s vitamin D level. 20-100 is considered normal though most studies in the NEJM 2007;357:266-81 article lean towards 40-100. <20 is deficiency and 20-39 seems insufficiency. Greater than 100 and definitely more than 150 is vitamin D toxicity
Foods that have vitamin Vitamin D – eh, not very many. Fresh wild salmon 3.5oz has 600-1000IU of vitamin D which is a healthy daily dose for most. Farmed raised salmon only has 100-250IU. Cod liver oil 1tsp has 400-1000IU – just like what I saw on The Waltons when the nurse practitioner tried to prevent rickets in the children. 1 serving of fortified milk, fortified OJ, infant formulas, fortified yogurt (8oz, not 6), fortified cheeses (3oz), and fortified breakfast cereals have 100IU of vitamin D.
But for those who don’t get enough sun exposure, it appears 800IU of vitamin D is what is needed to keep levels in good range. So over the counter vitamin D might be required. Rx vitamin D is also available for those in particular with osteoporosis or osteomalacia.
Osteomalacia means the quality of the bone is not healthy and that can cause bone pain. So there is an observation of people with bone pain who feel better once repleted with vitamin D.
Brain, prostate, breast, colon and muscles have vitamin D receptors. So there is also an observation of decreased muscle pain and less falling down with replacement of vitamin D in those who were deficient or insufficient. Also the immune system appears to work poorly if there is vitamin D and even a correlation of Type I diabetes with vitamin D deficiency. Tuberculosis appears to be more prevalent in those who are vitamin D deficient, such as in African Americans in northern climates. Arthritis appears to be improved with vitamin D levels in good standing. The NEJM also talks about other disorders that are associated with vitamin D but they appears to be weak links such has depression, schizophrenia, hypertension, heart disease, multiple sclerosis, and cancer.
Besides lack of sun exposure, there are some genetic causes or illnesses that can lead to vitamin D deficiency. Medicines that can destroy vitamin D include HIV medications, anticonvulsants, and glucocorticoids. Other things that can lead to vitamin D deficiency include: well, sunscreen, darker skin due to melanin, winter time, kidney disease, liver disease, and malabsorption syndromes
drjohnhong Uncategorized, food, Bones & Muscles, Endocrinology Comments (0) » |
16
May
2007
Obesity and fructose - how are they related? 2/3 of Americans are overweight or obese. It is getting worse the past couple of decades. High fructose is very common over the past couple of decades as well. High fructose is added to most sweet drinks and foods.
Fructose is a simple sugar similar in structure to glucose (the main sugar). Metabolism is
unique – mostly done by the gut organs. Digested into glucose, glycogen, lactate, or lipids. Does use insulin – so initially was studied in type II diabetics to see if was good alternative to sugar (glucose or sucrose). Initially digested appeared to be beneficial. Low dose fructose increase glucokinase and lowers liver production of glucose.
However, later in metabolism shown to associate with Metabolic Syndrome X: insulin resistance (diabetes or glucose intolerance) , bad cholesterol (high LDL and triglycerides), increased body fat, and high blood pressure. Increased uric acid as well that increases risk of gout and kidney stones. Nurses’ Health Study 1999 showed high-fructose correlated with high c-peptide levels (~insulin). Stimulates sympathetic nervous system which is why people might get a “boost” with high sugar/fructose.
Unlike sucrose (2 glucoses combined), fructose doesn’t signal to brain that the body is full – so overeating is common. High-fructose corn syrup in mice – drink more of this than sucrose sweetened water
drjohnhong Uncategorized, obesity, diabetes, food, weight Comments (0) » |
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