There are several comments posted by Japanese people living overseas, and they said that they upset their health after coming back temporarily to Japan. In addition, I heard a few stories about that foreign citizens upset their health, or were strongly suspected of internal exposure to radiation during their stay in Japan.
The followings are just a few of cases.
Case 1 A Japanese nationals living in West Coast stayed in Tokyo for a few months a year for these 3 years. She had the last checkup and found its TSH value near 30, then started to take the drug immediately. During her stay in Japan at midsummer in 2013, she shivered from cold and wore borrowing sweater. She purveyed her meals from Japanese supermarket in West Coast.
Case 2 A Japanese nationals living in Australia was at some place in Japan near the Sea of Japan with her daughter when the Great East Japan Earthquake occurred. They went to Toyama prefecture for safety in Mar.14. After that, they went to Haneda Airport by air in Mar 17 and went to Narita Airport by land soon. Then they departed to Australia around 21 o’clock on the same day. After going back to Australia, she suffered from menstrual problem and hair loss those she rarely experienced before. After a while, she came back to Japan twice about for 10 days each. During the first stay in Japan, she had pain and nagging feeling in her eyes. Just after the second stay in Japan, she felt chilly and suffered from severe iron deficiency. Although she recovered from iron deficiency by taking drugs, she still suffers from chill, pain and nagging feeling in her eyes and visual loss. In Australia, she ate foreign meals except Japanese seasonings like soy sauce and miso. According to her story, her Japanese friends in Australia cannot go back to Japan without falling sick, heart pain, fever and eye pain.
Case 3 A Japanese nationals living in Europe stayed at Kyoto for a month from Oct, 2011. She/he found blisters in her/his forehead during the second week. After that, her/his nose was runny for a while. After going back to Europe, she/he had got a big bruise upper back of the leg twice, and also suffered from cold-like symptoms for 2 weeks in 2013. Finally she/he developed cystitis in 2014.
Case 4 An American woman in her 20s participated in a study abroad program in Kyoto for three months, from the end of August through the end of November, 2011. During the penultimate week of her stay in Japan, she spent one week in Tokyo, Nikko and Sendai. She ate Sushi near Tsukiji Uoichiba in Tokyo, but she did not eat any fish in Nikko and Sendai. Also she did not eat any dairy during her short trip. While in Nikko, where she went hiking through forests of colorful maple leaves, she began experiencing strange headaches and fatigue. As she traveled by bullet train to Sendai, the train stopped in Fukushima. Her headache that was lingering for the past three days suddenly magnified into a piercing migraine. By the time she arrived in Sendai, her pain had completely dissipated. For the next three days, she felt fine. In mid-November she returned to Kyoto, where she spent her final week in Japan. During the last four days, she experienced a migraine again. She flew from Osaka to Tokyo and then from Tokyo to the U.S. During the entire transpacific flight, she felt unexplainable stabbing pains in her stomach, nausea and delirium. By the time she arrived back home, she felt relieved that her pain was gone. The following morning she woke up with a bloody nose. During the next month, she experienced daily nosebleeds, headaches and dizziness. She felt chronic fatigue and weakness. During the second week of December, she vomited for two days straight, uncontrollably purging all of the liquids from her body. On those days, she could not consume food. Her body became weak and drained of energy. She continued to have nosebleeds halfway into January. Since mid-January 2013, these symptoms have stopped.
Case 5 An unidentified foreign student came to Japan to study in April, 2011. She/he measured her/his exposure through WBC, which resulted in certain internal exposure caused by radioactive iodine. Then she/he was very surprised and went back to her/his home country immediately.
The followings are my guesses those are guided by these cases.
1. After Mar 15, 2011 in the area around Tokyo, there were still many radioactive substances in the air (indoors or not) after the radioactive plume had left. The inside of transportation is polluted. So did everything like clothing, furniture and bedding. Additionally people in Tokyo were exposed to the radiation by breathing polluted air.
2. Agricultural products have kept on being strongly polluted by radioactivity since Mar, 2011. Polluted agricultural products were distributed in large quantities in restaurant industry.
3. Food products around Kansai area (Kyoto and Osaka) in the autumn of 2011 seemed to be appreciably polluted by radioactivity. Since there is a high possibility that people living in Kansai area were exposed to the radiation by breathing polluted air, they are in danger of damaging their health for a long time.
4. I guess that American student in case 4 would have been exposed to the radiation since she was already in Kyoto. She ate polluted food in Kyoto, and was exposed to the radiation ever so much in Tokyo, Nikko and Tohoku district. For this reason she was plagued by ill health for a while even after returning home.
5. With regard to case 1 and 2, you would see that the more they came back to Japan, the stronger their body reacted to internal exposure. What we can learn from this is that it is possible for the people, who have been in Japan since Mar, 2011 and damage their health, to have even worse health problems especially after eating strongly polluted food.