I can't believe you would reference Wikipedia instead of the Biological Effects of Ionizing Radiation (BEIR) Reports.
YOUR links, showed different values for K-40 in the body;
Wikipedia stated "about" 30mg (did not state their reference).
Your link to ISU stated 17mg AND it states their data is from ICRP 30, a good reference.
Your link or ORAU doesn't state anything that I saw.
So I looked it up. This is what I got: There are 31 mg of K40 in a 75 kg person which gives an activity = 0.217 mCi = 8,000 Bq and 1.7x10-14 gms of C14 in a 75 kg person which gives an activity =.078 mCi = 2,900 Bq.
On the same subject, in a commentary for ASCH, Dr. Dade Moeller (BEIR VII panel) addressed people’s concern about radiation and said:
"For those who seek a radiation risk-free society, certain steps can be taken. They include:
Living at sea level, near the equator, in a well ventilated frame house, or as an alternative, in a wooden house-boat on a freshwater lake;
Avoiding mountain climbing, airline travel, cigarette smoking and the consumption of well waters and foods containing unusually high concentrations of naturally occurring radioactive materials.
Finally, if you find yourself in a crowded room and desire to keep your dose rate to minimum, you should always stand close to a woman -- to avoid receiving an unnecessarily high dose from k40."
Who says smart people don't have a sense of humor.