Ask the Tokyo Dietitian: Are trans fats still allowed in Japan? Plus your nutrition questions answered

Welcome to another installment of "Ask the Tokyo Dietitian,” where you can get expert insights on food and nutrition, tailored specifically for life in Japan.

Whether you're looking for tips on how to balance traditional Japanese foods with modern dietary needs, navigating local food labels or you want to learn more about the latest in nutrition science, our registered dietitian is here to help. Each month, we'll tackle common questions, dispel myths and provide practical advice to support your health and wellness journey.

Have a question? Ask away by emailing us at tokyodietitian@japantoday.com and your question may be featured in an upcoming article.

Question: I’ve heard that trans fats are still allowed in foods here. Is this true and if so, how can I avoid them?

Tokyo Dietitian: While Japan leads the world in many health-related metrics, such as long lifespans and low obesity rates, it’s certainly interesting that trans fats can still be used in foods here. Despite the 2018 call to action from the World Health Organization to eliminate all trans fats from the global food supply by 2023, Japan has been slow to adopt this and has not passed any regulation prohibiting the use of trans fats.

Some companies have voluntarily removed trans fats from products like snack foods or margarine. Yet, if you look in the aisles of a Japanese grocery store, you’ll likely find foods that contain partially hydrogenated oils. These types of oils are the most common form of artificial trans fats found in food.

So, what are trans fats? Why do we care if they are in our food or not? Unlike many topics in nutrition, there seems to be little disagreement that trans fats are horrible for one’s health due to their ability to increase the risk of heart disease, stroke and type 2 diabetes. Because of the chemical structure of artificially made trans fats, the body is unable to break them down easily, which in turn can increase LDL cholesterol levels. While the exact answer to why these fats are still in use in Japan is unknown, there are a few theories.

First, many Japanese food manufacturers have claimed that because the public consumes very little trans fats compared to other Western countries, there is less of a need to outlaw them. Next, partially hydrogenated oils are cheap, which makes switching to more expensive oils less appealing. Finally, rates of heart disease in Japan are also much lower than in its Western counterparts. In combination, this leaves little incentive for food producers to make the switch and reformulate their foods.

Even though Japan may take a more laid-back approach to trans fats, I would strongly suggest that consumers do their best to avoid these in foods. As per the guidance set forth by the WHO, people should try to limit their trans fat consumption to less than 1% of their total energy intake. As mentioned earlier, partially hydrogenated oils are most commonly found in snack foods like cakes, cookies, chips or crackers, fried foods and margarines — so be sure to read labels when purchasing these foods.

You can look for this kanji: 部分水素添加油脂 (partially hydrogenated oils).

Or you can use Google Translate to help you review the ingredient list on Japanese foods.

Q: Help! I’m living in Japan and trying to increase my fiber intake to improve my health, but I don’t know where to start. Which Japanese foods are high in fiber, and how much fiber do they contain?

TD: Well done on wanting to boost your fiber intake! The benefits of fiber are numerous and range from improving blood sugar levels and digestion, lowering cholesterol levels and increasing satiety levels. In my professional experience, most people are failing to reach the recommended fiber intake goals for their age and gender, which range from 21 to 38 grams per day as per the U.S. public health guidelines. Therefore, I think it’s great that you want to add more fiber to your diet, and lucky for you, Japan has many fiber-rich foods to choose from.

While this is not a complete list of all high-fiber Japanese foods, below are a few of my personal favorites. Please note that the fiber content listed is approximate and may vary depending on source, preparation and other factors.

Fruits and vegetables:

• Gobo (burdock root) = 3.3-5.7 grams per 100 grams
• Nashi (Japanese pear) = 4 grams per 100 grams
• Kaki (Japanese persimmon) = 3.6 grams per 100 grams
• Satsumaimo (sweet potato) = 3 grams per 100 grams
• Enoki, maitake or shiitake (Japanese mushrooms) = 2.5 grams per 100 grams

Soy-based foods:

• Natto (fermented soybeans) = 5 grams per 100 grams
• Edamame (green soybeans) = 5 grams per 100 grams

Grains and starches:

• Soba (buckwheat) noodles = 3-4 grams per 100 grams cooked; will depend on the percentage of buckwheat used
• Genmai (unpolished brown rice) = 1.6 grams per 100 grams cooked
• Mugi (barley) = 3.8 grams per 100 grams cooked

Beans and seeds:

• Azuki (red beans) = 7.3 grams per 100 grams cooked
• Goma (sesame seeds) = 12 grams per 100 grams

Need help on how to use these foods to make high-fiber meals and snacks? Here are five suggestions you can try at home:

1. Add mushrooms and shelled edamame to your stir-fry
2. Like eating natto with rice? Try switching your rice from white to brown for a high-fiber snack
3. Throw in a diced pear or persimmon to your salads
4. Combine red beans with brown rice and sesame seeds for a healthy twist on sekihan, a traditional rice dish
5. Make kinpira gobo, a side dish made from stir-fried burdock root, and serve with meals or in a bento

With these ideas, you’ll be able to hit your fiber goal in a delicious and nutritious way. Enjoy and keep up the great work on improving your health!

Victoria Lindsay, MS RD, is a registered dietitian and nutrition consultant working at Tokyo Medical & Surgical Clinic and her Tokyo-based private practice. To get in touch, please visit: www.victorialindsayrd.com.

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