My AF seems less frequent in the summer. Maybe it is because I get more sun exposure and thus more vitamin D. The comment on tea could be of interest to tea drinkers. I found this information on the website below. Hopefully, this info has not already been posted.
Is magnesium’s absorption blocked?
Calcium and magnesium compete for absorption and so too much calcium in the diet will block magnesium absorption. Our physiological requirement ratio for calcium to magnesium is about 2:1. In dairy products the ratio is 10:1. So, consuming a lot of dairy products will induce a magnesium deficiency.
Tea contains tannin, which binds up and chelates all minerals including magnesium. If tea is to be drunk, don’t have it with food. Incidentally, tea drinking is a common cause of iron deficiency anaemia in the UK for this same reason.
Vitamin D is necessary for the body to utilise magnesium. The only significant source of vitamin D is direct sunshine on the skin (the effect is not the same through glass). Only a small amount is required to make a difference – 10 minutes a day on the face and hands has an effect. One hour of whole body sunshine in summer can produce 10.000iu! The RDA for vit D is set ridiculously low at 400iu – in America it has just been raised further, but I like people to have at least 2,000iu and many people I recommend 10,000iu daily. At this level of dosing there are no side effects and no toxicity. In winter, in our climate, we should all be taking vitamin D.
Hypochlorhydria – magnesium requires an acid environment for its absorption and hypochlorhydria will result in poor magnesium absorption. See Heartburn - at last I have sussed out why this is such a common problem!. Actually I see this problem very commonly in CFS!
Here the excerpt on heartburn:
Heartburn
Gastro Oesophageal Reflux Disease (GORD)
In this condition, the patient experiences pain behind the breast bone, particularly after eating as a result of the acid contents of the stomach refluxing into the oesophagus. There is no doubt there has been a great increase in this condition, resulting in a great many patients having to take acid blockers such as Losec to control this symptom. Excessive acid in the stomach can be caused by Helicobacter-Pylori infection, but I have now heard from two Consultant Gastroenterologists that if they discover H-Pylori in the stomach they do not use eradication therapy because it does not seem to help the gastro-oesophogeal reflux.
For some time I have pondered over the explanation for this because it did not really seem to make sense, but I think now I have a possible answer.
The normal oesophagus is neutral at pH 7. Normal stomach contents is extremely acid at say pH 2-4, the normal duodenum is alkaline at pH 8. As foods are eaten and enter the stomach, the effect of the food arriving dilutes stomach contents and the acidity rises. The stomach pours in acid to allow digestion of proteins to take place and the pH falls back down to its normal value of 2. The key to understanding GORD is the pyloric sphincter, which is the muscle which controls emptying of the stomach into the duodenum. This muscle is acid sensitive and it only relaxes when the acidity of the stomach is correct, i.e. 2-4. At this point stomach contents can pass into the duodenum (where they are neutralised by bicarbonate released in dribs and drabs from the bile ducts).
If the stomach does not produce enough acid and the pH is only say 5, then the muscle which allows the stomach to empty (the pyloric sphincter) will not open up (dilate). When the stomach contracts in order to move food into the duodenum, the progress of the food is blocked by this contracted pyloric sphincter. But of course the pressure in the stomach increases and the food gets squirted back up into the oesophagus. Although this food is not very acid (not acid enough to relax the pyloric sphincter), it is certainly acid enough to burn the oesophagus and so one gets the symptoms of gastro-oesophagial reflux. The paradox is that this symptom is caused by not enough stomach acid! i.e. the reverse of what is generally believed!
Antacid doesn't cure...
Of course, the symptoms can be totally alleviated by blocking stomach acid production completely. This is why drugs such as Gaviscon, Zantac (H2 blockers) and Losec (proton pump inhibitors) work. It also explains why eradicating H-pylori does not help in GORD. This is because eradication of H. pylori has the effect of reducing stomach acidity, not increasing it!
Use of drugs, therefore, whilst they may relieve the symptoms in the short term, usually mean that the patient has to take these drugs regularly in the long term in order to prevent their symptom from recurring. This may be excellent news for drug company profits, but I am concerned about the long term blockage of stomach acid production. First of all stomach acid is highly necessary for the effective digestion of proteins. It may well be that if proteins are not digested this could have adverse effects lower down in the gut as well as the problems of protein malabsorption. The second point is that the acid stomach kills bacteria in food and the upper part of the gut the small intestine is meant to be sterile. If this acid production is blocked then one can expect to get bacterial and possibly yeast overgrowth of the upper gut and this may also have long term problems. For example in Japan where hypochlorhydria (no stomach acid) is extremely common, there is the highest incidence of stomach cancer in the world. Taking acid blockers is a major risk factor for osteoporosis because minerals require an acid environment for their aborption.
Therefore, the worst thing in the long term that one can do for this condition is block acid production because this makes one more likely to get all the above complications.
... but acid might!
The answer is to give patients more acid in order to allow the pyloric sphincter to open properly and prevent reflux. The problem with this intervention is that initially the symptoms of GORD may be made much worse. The key is to change the diet first. See Acidity and ulcer disease.
The treatment is to take betaine hydrochloride or ascorbic acid with food in order to make stomach contents as acid as possible in order that the pyloric sphincter will work properly. Small meals will also help so that the stomach finds it easier to become acid, furthermore do not dilute that acid by drinking a lot of fluid with a meal. It may be worth using a medicine which coats the oesophagus, such as De-Nol, or one of the herbal preparations such as Mastica which has no effect on stomach acidity. In the short term one could try one of the drugs which helps relax the pyloric sphincter, such as metoclopramide.
Also see Hypochlorhydria.
GORD and allergy
Finally, it should always be borne in mind that GORD can certainly be caused by allergy and if I had a patient who also had other symptoms such as headache and irritable bowel syndrome, then it would be well worth trying an elimination diet.
Is it GORD?
It can be difficult to distinguish between pain due to GORD and pain due to angina. If in doubt consult your doctor! What usually gives the game away is exercise - this makes angina worse but should have little effect on GORD.
Magnesium as a supplement
Magnesium supplements 
Magnesium supplements 
Thoughts on Magnesium? 
Potassium and Magnesium
