Monday, July 15, 2019

Does zinc supplementation reduce absorption of calcium or magnesium?

In general, no.  While it’s true that zinc can reduce absorption of calcium it would have to be a high level to do so; studies showing such a relationship have primarily been on zinc sulfate supplements containing about 140 mg of elemental zinc.  This is far above the RDA/DV level of 15 mg. typically found in dietary supplements, or even the 30-50 mg. found in some immune or prostate formulas.  One typical study used 142 mg/day of zinc to achieve this; far higher than the amount in supplement formulas.  The study noted that the decrease in calcium absorption occurred when low calcium and high zinc intake was noted, but not with adequate calcium intake, and specifically tested lower doses of zinc along with low calcium intake and did not find a reduced absorption of calcium at commonly supplemented levels:

So the issue is limited to a very high zinc intake combined with a very low calcium intake, not the levels found in common supplements.  One will find zinc and calcium together in multiple vitamins or some mineral formulas, but at typically available levels they are not shown to cause the reduced absorption of calcium found in those studies cited above. 
The issue has also been studied for magnesium versus zinc intake.  Likewise, very high zinc intake interfered with low calcium intake (500 mg.) but less likely at higher levels of calcium intake.  Again, the levels of zinc in question (around 140 mg.) are not typically found in over-the-counter zinc supplements or multivitamins. 
 It is more convenient for people to supplement with combination formulations instead of taking several single ingredient supplements, typically increasing compliance with label instructions and dosing.  Knowing that it's okay to take minerals in combinations that are commonly found in the marketplace is reassuring when some pundits claim that it is inappropriate based on the unusual circumstances of low mineral intake combined with abnormally high zinc intake.  For physicians prescribing the high strength zinc products, this is something to consider, but not something for consumers of dietary supplement formulas to be concerned about.

Wednesday, June 27, 2018

Foods and Supplements for a Ketogenic Diet

Ketosis occurs when the body is largely starved of carbohydrates but has an alternate energy source. Ketogenic products encourage the burning of fat in place of sugar/carbohydrates as a caloric source. The key is to avoid rises in blood sugar and insulin, while providing alternate fuels.

There are numerous keto-friendly products; these are considered to be those that contain fewer than 10 calories per serving of net carbohydrates (minus fiber). Fiber doesn’t raise blood sugar and insulin response, so is neutral and not counted when looking at labels. Most dietary supplements fall into the category of being ketogenic neutral; that is, they neither contain significant carbohydrate sources nor directly contribute ketogenic stimulating substances like fat. The main ketogenic products are fats: MCT and coconut oils (both contain MCTs) are the most important ones. Some take beta-hydroxybutyric acid, a ketone, directly.

Ketogenic diets tend to decrease electrolytes and increase the need for water. This increases the need for magnesium, potassium, and even sodium. If blood sugar drops too low, the kidneys can create blood sugar by converting the proteins (i.e. the amino acid glutamine) into glucose (gluconeogenesis), so high protein diets are also discouraged. This leaves non-starchy vegetables and fats as the most desirable parts of the diet, along with some protein and fiber. Nuts and seeds are often okay, but some are more starchy; check the labels. Dairy is largely out due to its lactose content, but non-dairy foods and beverages may be okay if also low carb. Fish oil supplements are desirable. Green foods are important; supplements like chlorella or spirulina can be very useful, as can wheatgrass or barley grass.

Other supplements used on a ketogenic regime include green tea and EGCg capsules, L-glutamine if exercising (it can convert to sugar, so use sparingly), 7-keto DHEA, collagen or gelatin or bone broth. Anti-inflammatory substances may also be helpful: turmeric and curcumin, ginger, etc.

Unless eating natural or fortified sources of vitamin D, or getting adequate sun exposure, supplementation of this vitamin is recommended. A multiple vitamin is the best source, assuming it has enough for your needs,  as it also supplies other nutrients needed for metabolism of fats and energy production. Calcium supplementation may be needed unless consuming lots of green vegetables. Look for digestive enzymes that supply lipase if consuming lots of fat (not needed for MCT oil). Supplements containing ox bile (also in some digestive enzyme formulas) may be needed if inadequate gall bladder function is suspected or known. Don’t forget the electrolytes!

Thursday, December 28, 2017

Stearic acid and Magnesium Stearate update

How much stearic acid is in chocolate? 

We were looking at a chocolate bar yesterday. Dark chocolate is supposed to be a health food. 

As we happened to be nutritionists, the topic of the chocolate bar's stearic acid content came up, which is a controversial fatty acid. So I did a little calculating...

The bar in question is a 72% Dark Chocolate from Belgium, with the fat coming almost exclusively from cocoa butter (except a tiny bit of lecithin; but typically under half a percent is used in chocolate manufacturing, according to Chocolate University Online). The bar weighs 1.65 oz (47 grams), contains 280 calories, and is labeled as being one serving.  

The product label says that the bar supplies 19 grams of fat, including 12 grams of saturated fat. Since about one-third of cocoa butter’s fat - and over half of its saturated fat - is known to be stearic acid, a one-bar serving of this chocolate conservatively can be assumed to contain at least 6 grams of stearic acid, which is equivalent to 6,000 milligrams (mg.). 

How does that compare to the amount of stearates commonly found in tablets and capsules?

That amount in the single small chocolate bar is equivalent to more than 1,000 tablets or capsules worth of stearate content, assuming the highest likely amount of stearic acid or magnesium stearate was used in those pills. Five milligrams is the highest I've seen on supplement Master Formulas, but many products use less or none. (Assuming 5 mg. per pill x 1,000 pills = 5,000 mg. of stearates per bottle).

So if someone had a jumbo, family-sized bottle of a thousand pills, each containing a few milligrams of stearic acid or magnesium stearate that's primarily stearic acid, that whole bottle would contain less stearic acid than a single serving 47 gram dark chocolate bar. 

Doesn't that put stearic acid consumption into perspective? Each pill contains less than 1% of what you'd get in a serving of chocolate. 

How much stearic acid is found in other common foods?

Butter contains about 12% stearic acid, by weight, as do the average beef, pork, or lamb product. Healthy olive and coconut oils contain between 2-3% stearic acid. Salmon oil naturally contains about 4% stearic acid. 

More fun facts:
  • Milligrams (mg.) are thousands of a gram; micrograms (mcg.) are millionths of a gram.
  • Stearic acid tends to be converted into oleic acid in the liver.
  • Stearic acid is abundant in the food supply as a natural component of the fat in those foods; milk and meat fats are the primary sources. 

How much magnesium is in magnesium stearate?

The molecular weight of stearic acid (Octadecanoic acid) is 284.484 grams/mol. There are 2 stearic acid molecules in one molecule of magnesium stearate, which has a molecular weight of 591.257 grams/molThe molecular weight of magnesium is about 24.305 grams/mol. So the amount of magnesium in a 5 mg portion of magnesium stearate is about 200 micrograms (not milligrams); about half of one one-thousandth (half of 1/1,000 or 0.0005 or 0.050%) of the 400 milligram RDA. That's also 1/20th of a percent of the RDA. 

So the amount of magesium in a pill containing magnesium stearate is negligible; it would be insignificant unless another magnesium source is added. Magnesium stearate is a form of chelated magnesium that contains only about 4% elemental magnesium by weight and about 96% stearic acid.

  • Kelly FD, Sinclair AJ, Mann NJ, Turner AH, Abedin L, Li D. A stearic acid-rich diet improves thrombogenic and atherogenic risk factor profiles in healthy males. Eur J Clin Nutr. 2001 Feb;55(2):88-96. PubMed PMID: 11305631.

Wednesday, September 06, 2017

Fish Oils: ethyl ester or triglyceride or...?

Most fish oils today are molecularly distilled, changing them from their natural triglyceride forms to ethyl ester (esterified) forms.
Anything stronger than a natural strength fish oil (up to about 30% EPA+DHA combined) is typically concentrated by molecular (vacuum) distillation to allow vaporizing at low temperatures, in the process converting to the ethyl ester form. This allows separation of the fatty acid constituents in order to add back some of the desired omega-3 fatty acids in order to concentrate them up to 60% or higher levels of the oil. This is accomplished by removing undesired fractions that were separated by the distillation, such as cholesterol, triglycerides, and various other fatty acids.

Because of the warming oceans, the naturally occurring amount of omega-3 fatty acids in most fish have declined from historically about 30% to somewhat less. Due to this change, most fish oil supplements containing 180 mg. of EPA and 120 mg. of DHA (300 mg. combined in a 1,000 mg. fish oil capsule) now need to spike the potencies by adding additional EPA and DHA fractionated from the original oils by molecular distillation. It is now unusual to find even a low strength fish oil capsule that is not at least partially molecularly distilled into ethyl ester forms. 

Some of these distilled oils are then partially reconverted to a triglyceride form in a process called reconversion that involves adding back 20% or more triglycerides to the esterified fatty acids to try to reattach the triglycerides to the fatty acids with enzymes. This imperfectly produces a highly processed combination of both triglyceride and mono-and-diglyceride forms of omega-3 with many of the original oil’s natural constituents deliberately removed (cholesterol, omega-6, omega-9, stearates, et al). This newly engineered combination is called a reconverted triglyceride form (rTG) containing typically at least 60% triglyceride form fatty acids that’s distinct from the original triglyceride (TG) form, but is as far from the original triglyceride form as can be produced by intentional chemical manipulation. Numerous brands offer this rTG form and inaccurately call it a natural triglyceride form, when it is in fact far removed from that oil.

This is done because of a prevailing and largely disproven belief that the natural triglyceride form is best. That's certainly untrue for cardiology and the form has recently been shown to be largely irrelevant to absorption and efficacy in general. 

Tuesday, August 08, 2017

Is Carrageenan Safe or Dangerous?

Undenatured carrageenan is a natural stabilizer, binding agent, and emulsifier used in products such as toothpaste in place of SLS and other truly undesirable ingredients commonly used in mass market products. It is also used in some vegan-friendly softgel capsule material as an alternative to animal-derived gelatin.

There is an Internet myth that carrageenan is unsafe; due primarily to confusion with a so-called “denatured carrageenan” polymer that is actually poligeenan, a heavily processed low molecular weight seaweed derivative currently used only as an x-ray imaging component. Poligeenan, previously used in pharmaceuticals, is quite different from the undenatured high molecular weight material that we use. Due to the safety concerns over poligeenan, regulations routinely require the carrageenan added to foods to have high molecular weight to ensure its integrity. But there are no unresolved safety concerns with undenatured carrageenan. 

Carrageenan has been thoroughly vetted by national and international public health authorities over a number of decades, even recently in response to the ongoing blogger-driven controversies, so there is no remaining basis of concern. Even its use in infant formulas was recently reconfirmed to be safe, and it’s helpful in distributing the nutrients more evenly to avoid the settling out that could otherwise cause uneven nutrient intake when a bottle is only partially consumed. 

After repeated investigations, the evidence for carrageenan safety is stronger than ever. Carrageenan is extremely safe and present in a number of healthy seaweeds; only the denatured form of carrageenan - a drug - is toxic. 


·        Public health and carrageenan regulation: a review and analysis. Borowitzka et al. (eds.), Nineteenth International Seaweed Symposium. DOI: 10.1007/978-1-4020-9619-8_8. Developments in Applied Phycology.

Friday, January 20, 2017

Is Sorbitol Natural?

Sorbitol is a "sugar alcohol" that occurs naturally in various fruits (apples, peaches, nectarines, plums, grapes, cherries, apricots, pears, rose hips, berries, dates, coconut) at levels of 1% or more. Wasabi can contain up to 11%, and common dried fruits (prunes, pears) almost the same level. Of course, beer would be expected to have small amounts, as well. 

Sorbitol can be commericially produced from glucose. Non-GMO sources are available. 

In higher doses (30-50 grams) sorbitol can be laxative, but it is a useful non-cariogenic sweetener that doesn't promote dental caries (cavities). 

Wednesday, December 21, 2016

Is Aromatherapy Safe for Pets?

The skin of animals is much more sensitive than people’s, so essential oils should always be used with caution.  Don’t use essential oils directly on the fur/skin of cats. While cats are considered more sensitive to the oils than dogs, both are far more sensitive than us, so even a little in an enclosed space could be overwhelming to them. 

The oils are considered potentially harmful to dogs and cats if eaten. For example, eucalyptus oil can cause stomach upset, and in high doses liver toxicity. Eucalyptus oil can also damage the ear canal of cats if applied directly. Other oils may have similar or different risks. 

Birds are not advised to be near aromatherapy oils at all, as they are potentially even more delicate in regard to smells than dogs and cats. 

Diffusing is likely safer than direct topical appliucation or letting the pet actually consume the oil, but it still represents some risk depending on the type and amount of oil used, the room size, the diffusion method, and the amount of fresh air entering and circulating in the room. Never diffuse essential oils diluted into carrier oils; always use 100% pure essential oils only. 

Be cautious and safe with essential oils around pets by avoiding excess exposure, concentrations of aromas, or opportunities for the animals to lick or otherwise consume them! If in doubt, don't do it.