Thursday 23 May 2013

Phytic Acid Nutrients

MineralAbsorption factor by removing / lowering phytic acidAverageRDA
Calciumx1.3, x1.2 1.251,000 --> 800mg
(WAPF: 680 --> 544mg)
Magnesiumx2.52.5420 --> 168mg
Zinchigh/no: x6.2, x4.8; high/low: x3.2, x1.6/1.5,
x1.5, x1.42.1 
3.5411 --> 3.1mg
Ironx1.5, x2.1/1.7 1.7718 --> 10.2mg
Manganesex2.32.32.3 --> 1.0mg
Copperx2.1/2.4V, x1.1^1.150.9 --> 0.78mg
Phosphorusx1.46, x1.5 (estimates)1.48700 --> 473mg
(WAPF: 1300 --> 878mg)


Actual requirements studied here:


Although the need predicted by phytic acid removal is only ~168mg of magnesium, most people are deficient because our soils are depleted due to industrial farming and artificial fertilisers, and our water is no longer a good source as it's removal at source because it damages pipes. For this reason I will not be lowering the RDA of magnesium and recommend supplementation to ensure sufficient intake.


Although only ~1mg of manganese is needed due to lack of phytic acid, a meat and liver based diet only provides ~0.5mg, as manganese is needed for carbohydrate metabolism it's likely this is sufficient. Shellfish, such as mussels, are rich in manganese though so for those concerned are a great addition, as are bass, trout, and pike. Spices too such as cloves, ginger, cinnamon, spearmint, and turmeric are also fairly rich in manganese. Tea is very rich in manganese but may be poorly absorbed due to the tannins it contains.

Copper & Zinc:

The USDA RDA for copper and zinc are 0.9mg and 11mg respectively. My original menu provided 1.9mg and 22.9mg respectively. Both give a zinc/copper ratio ~12 so it's likely that this ratio is the ideal.

Although copper need based on absorption factors above predicts that less copper is needed than zinc, more important is the ratio, with ideal being ~12, at 0.78mg copper this means you need ~9.4mg zinc, easily achievable on a carnivore diet with plenty of meat.

Meat needs to be balanced with liver, especially lamb/beef liver which are very rich in copper to keep this ratio optimum. Pork liver in less rich in copper, instead being richer in iron.

Copper & Iron:

Copper and iron deficiencies can cause hypothyroidism, most plants have plenty of copper and grains are fortified with iron. Some cases of lower thyroid function in low/zero-carb may be due to lowered intakes of copper and iron due to relying only on muscle meat, these minerals are needed to convert the inactive T4 to the active T3 and may be a reason why we see lowered T3 in low/zero-carb diets (though lowered T3 in of itself is not hypothyroidism). Muscle meats have lots of zinc, very little copper, and are ok for iron; organs though, like liver, are very rich in copper and iron. Adding liver to a low/zero-carb diet will likely help thyroid function if it's caused by these deficiencies (link and link). Too high copper will also decrease iron absorption though, so all these minerals need to be balanced properly.


Dose rangeApproximate daily intakesHealth outcomes
>5.0 mg/kg bw(350mg/70kg)Gastrointestinal metallothionein induced (possible
differing effects of acute and chronic exposure)
100 µg/kg bw(7mg/70kg)Plateau of absorption maintained; homeostatic
mechanisms regulate absorption of copper
34 µg/kg bw(2.38mg/70kg)Hepatic uptake, sequestration and excretion effect homeostasis;
glutathione-dependent uptake of copper; binding to
metallothionein; and lysosomal excretion of copper
11 µg/kg bw(0.77mg/70kg)Biliary excretion and gastrointestinal uptake normal
9 µg/kg bw(0.63mg/70kg)Hepatic deposit(s) reduced; conservation of
 endogenous copper; gastrointestinal absorption increased
8.5 µg/kg bw(0.595mg/70kg)Negative copper balance
5.2 µg/kg bw(0.364mg/70kg)Functional defects, such as lysyl oxidase and superoxide
dismutase activities reduced; impaired substrate metabolism
2 µg/kg bw(0.14mg/70kg)Peripheral pools disrupted; gross dysfunction and disturbance
of metabolism of other nutrients; death
My final recommendation for copper will be 1-2.4mg, and zinc to be in the x12 ratio still.

Many already have too much copper though due to toxic build up from too much plant foods and so my diet will have slightly on the lower side of the copper range in order to help regain balance. Therefore. my diet will use mainly pork liver as it is low in copper (instead being richer in iron), this also allows for more liver and therefore vitamin A in the diet (see fat soluble vitamins recommendations), but still provides plenty of copper. As you will see in the final post this choice of liver is perfect for balanced nutrition when other copper-rich foods such as kidneys are also included.

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