Nutrition in vegetables and meats accurate?


I’ve been doing keto since July 26th. and have lost 68 lbs!! I did have some trouble with heat rate spikes and bp spikes that started a month ago. They are pretty much gone now, but I’ve been spending a lot of time thinking about electrolytes.

So, while these may seem like odd questions, they are rooted in my frightening experience.

I keep hearing/reading that vegetables don’t have as much nutrition as they used to have (magnesium, potassium, etc). I naturally wonder if the nutrition listed for vegetables in my food tracker are even remotely up to date.

Second, of the foods we eat (meat & fat, veggies), is the amount of nutrition actually absorbed calculated for the “average” person, or is that an estimate of what is available (raw or cooked) and has the potential to be absorbed? Probably the second, right. So are there studies that have been done showing what people actually might absorb?

Say, if my app tells me I’ve received X amount of magnesium from veggies and meat, I calculate that into how much I supplement. But is that even close to being accurate? I know. I’m over thinking this. Still.

Also, if you supplement with magnesium, do you just add 300 mg to what you have supposedly consumed in your food, or calculate it out with a goal of… say 600 mg total of magnesium daily from food and supplements? Just wondering how others do this.

I think I’ve figured out that it was related to too low magnesium (I had been taking magnesium Oxide, and not getting much in food and possibly also too little potassium. So I am carefully watching what I eat and take as a supplement.

Since increasing potassium from food and supplements and changing to magnesium bisglycinate I’ve not been aware of bp spikes or of my heart skipping a beat. But what do you do? How much do you try to get daily? I read all over the place that a person should get at least 300 mg, but I think that’s just not enough for me. Am I the only one who is affected this way?

Any way, thanks!


I seem to need more magnesium than others - certain times of the month I need to supplement about 800mg to avoid migraines. Most people find their magnesium limit based on their bathroom habits - too loose usually means too much magnesium. I don’t really supplement potassium at all other than the odd pinch of lite salt in my coffee - keeping my magnesium/sodium in check tends to work fine for me. It will be different for everybody.

As to the accuracy of nutritional info on the web - I think it’s about as good or accurate as it’s going to get. Different growing conditions, different cooking methods, different individual genetic makeups & different gut environments are all going to make a difference to how much you get & how much you absorb. Near enough is good enough in most cases.

(Robert C) #3

I do not do all this math and instead get a blood test.

You can calculate and take (for example) magnesium but still be “lab low” on a blood test.

Google and you’ll find oral magnesium absorption rates can be quite low (20%) depending on lots of factors (even what is already in your gut). But, is taking 5X what you calculate a good idea - what if your absorption rate is 50% or 70%? Can you overdose and how would you know if you did?

Maybe an Epsom salt bath is a better delivery mechanism for you if your oral absorption rate is really bad.

Supplements are usually highly concentrated and are much more in a single pill bursting open in your gut than you were ever expected to handle.

I discontinue ALL supplements for a while and get a blood test - you might want to do the same.

Then, look for a safe method (bath, low dose time release etc.) if your blood tests show “lab low” but otherwise I would stop guessing.

(Carl Keller) #4

I’m not much of a supplementer. I believe in trying to get what I need through what I eat and if we are tracking and conscious of what we are getting and lacking and trying to eat foods that give us balanced nutrition, we are way ahead of the majority of the population.That’s not to say that supplementing can’t improve your nutrition. There’s a lot of people here who supplement potassium and magnesium and it works for them.

Not sure what tracker you use, but I trust . It’s a pretty amazing tool.

I wonder about this too. Apparently our soils are so depleted, that the vegetables we grow in them are abosorbing way less nutrients than they used to. I did learn how they determine what nutrients are in a vegetable but I have no idea how often or varied this information is.

"For vitamins & minerals, there are individual different methods for each vitamin & mineral. For minerals, we can either do wet chemistries or atomic absorption spectroscopy (AAS). Wet chemistries which is when a scientist will add different solutions to the food till a chemical reaction occurs, like a change of color or a formation of a solid in a liquid solution. AAS is when we put the ash, or burnt up remains of the food, into water. We then fire a beam at the water & measure the light bounced out of the water, kind of like a prism. The color & amount of the light reflects what type & how much of mineral is present.

For vitamins, every vitamin is a bit different. Often times, though, we compare a solution with a known certain of the vitamin to the food solution & calculate the difference between the two. Ask me when you’re 10 for specifics."


Even from supplements, absorption is questionable. Some sources say magnesium bisglycinate is up to 70% absorb-able, others say only 20%!

It’s all because of my very frightening experience, and that magnesium supplementation has been SO helpful that I wonder about all this.

I have been watching videos by Carolyn Dean, MD, ND. She strongly encourages 700 mg of magnesium, saying everyone is deficient. She also says 700 mg of calcium total daily (not more) to go along with the magnesium. She sounds very knowledgeable, but of course, she is selling her own supplements, so it’s difficult to know if she is trust worthy. Also, she says not to take it all at one time, but to spread it out.

I have had my blood tested several times recently and my potassium was “on the low side of normal” and magnesium was “OK” according to the doctors, but I also question what is now considered “normal”. Also, since magnesium has helped me SO VERY much, I’m certain I wasn’t getting enough! I don’t really trust the blood levels. I’ve read that the body works really hard to keep certain amounts in the blood, drawing if from cells in the body, so the tests are not always a good indicator.

Thanks for the replys!!