Hong Kong, February 2025 – A new investigation by the Hong Kong Consumer Council has shattered the common belief that certain sugars are significantly healthier than others, revealing that all six popular varieties—including brown sugar, rock candy, and raw slab sugar—contain no detectable iron, while darker sugars offer only marginal mineral benefits that are negligible in typical serving sizes. The findings, published in the council’s latest Choice magazine issue, challenge long-held assumptions about the nutritional superiority of traditional sugars and urge consumers to look beyond color and name when making dietary choices.
The Six Sugars Under the Microscope
The Consumer Council examined six common types of sugar available in Hong Kong: raw slab sugar (蔗片糖), red sugar (紅糖), dark brown sugar (黑糖), light brown sugar (黃糖), white sugar (白砂糖), and rock candy (冰糖). Each variety differs in production method, purity, and color, but the council’s laboratory tests revealed that none of them contain detectable iron—a nutrient often associated with “blood-building” claims in traditional Chinese medicine.
How They Are Made: Tradition vs. Modern Processing
Traditional methods involve extracting juice from sugarcane or sugar beets, filtering impurities, and boiling the liquid until it crystallizes. Sugars like raw slab sugar, red sugar, dark brown sugar, and light brown sugar are partially refined—they skip the “centrifugation” step that separates sugar crystals from molasses. This leaves behind some minerals and gives them their characteristic colors and flavors.
However, many modern manufacturers now produce these sugars by starting with white sugar and adding molasses or caramel coloring. This shortcut reduces costs but also strips away the very nutrients consumers assume they are getting. The Consumer Council advises shoppers to check ingredient labels carefully: if molasses or artificial colorings are listed, the product is likely a processed imitation, not a traditionally made sugar.
Nutritional Breakdown: What the Tests Found
Darker Sugars Contain More Calcium and Potassium—But Not Enough to Matter
The council’s laboratory analysis showed that darker sugars—raw slab sugar, red sugar, dark brown sugar, and light brown sugar—contain measurable amounts of calcium and potassium. Dark brown sugar had the highest calcium content, ranging from 18 to 127 milligrams per 100 grams, while raw slab sugar led in potassium, with up to 944 milligrams per 100 grams. In contrast, white sugar and rock candy showed little to no detectable minerals.
However, the council emphasized that even the most mineral-rich sugars provide negligible amounts in real-world use. One level teaspoon (about 6 grams) of dark brown sugar delivers only about 1% of the recommended daily calcium intake and 3% of the recommended potassium intake for adults aged 18 to 75. “These sugars should not be relied upon as a primary source of calcium or potassium,” the report stated.
Iron: A Complete Absence Across All Samples
In a finding that may surprise many, none of the tested samples contained any detectable iron. This contradicts traditional Chinese medicine beliefs that certain sugars, particularly red and dark brown varieties, can help “build blood” and prevent anemia. Dr. Lo Kwai-ching, a lecturer at the University of Hong Kong’s School of Chinese Medicine, acknowledged the discrepancy, explaining that while modern chemical analysis shows no iron, traditional Chinese medicine attributes “blood-nourishing” properties to these sugars based on their energetic qualities and historical use in herbal formulations.
Calorie Reality Check: One Teaspoon Costs Seven Minutes of Walking
All sugars are calorically dense. A single teaspoon provides about 24 kilocalories—enough that a 60-kilogram adult would need to walk at 3 kilometers per hour for roughly seven minutes (about 350 meters) to burn it off. The council warns that even “healthier” darker sugars are not low-calorie alternatives.
Purity and Sugar Content
Light brown sugar and white sugar had the highest purity, averaging nearly 100% total sugar content per 100 grams. Raw slab sugar had the lowest average total sugar content at about 92%, due to higher levels of molasses and moisture. Among all samples, total sugar content varied by as much as 6% to 7% between brands of the same type.
Traditional Chinese Medicine Perspectives: More Than Just Nutrition
Dr. Lo Kwai-ching, a Chinese medicine practitioner and lecturer at the University of Hong Kong, provided insights into how each sugar is traditionally used:
- Raw slab sugar: Believed to strengthen the spleen, moisten the lungs, and nourish blood. Recommended for those with weak digestion or lung dryness. A classic recipe is 鸳鸯番薯糖水 (sweet potato soup with ginger), which combines fiber-rich sweet potatoes with warming ginger.
- Red sugar and light brown sugar: Used to harmonize the spleen and liver, promote blood circulation, and alleviate cold hands and feet. Dr. Lo suggests red sugar ginger tea for those with a cold constitution.
- Dark brown sugar: Known for warming the spleen and dispelling cold, it is often recommended for menstrual pain and cold extremities. Recipes include dark brown sugar ginger tea and dark brown sugar four-substance soup.
- White sugar: Considered neutral in nature and used to tonify the middle burner, but traditional Chinese medicine rarely uses it due to modern bleaching processes.
- Rock candy: Valued for its moistening and yin-nourishing properties, ideal for dry throat and skin. A popular preparation is rock candy pear and almond tea.
Dr. Lo cautioned that modern processed versions—made by adding molasses to white sugar—may not carry the same therapeutic benefits as traditionally crafted sugars.
Practical Takeaways for Consumers
- Check the ingredient list: If a product lists “molasses” or “caramel color,” it is likely made from refined white sugar, not traditional methods.
- Don’t rely on sugar for minerals: Even the most mineral-rich varieties provide only 1% to 3% of daily calcium and potassium needs per teaspoon.
- Watch your portions: One teaspoon of any sugar contains about 24 calories. A 60-kilogram adult would need to walk for seven minutes to burn that off.
- Consider traditional uses: For specific health goals—like warming the body or soothing a dry throat—choose sugars based on their traditional Chinese medicine properties, but remember that modern processed versions may not offer the same benefits.
The Bigger Picture: What This Means for Your Kitchen
The Consumer Council’s findings serve as a reality check for health-conscious consumers. While darker sugars do contain trace minerals, the amounts are too small to make a meaningful dietary impact. The real takeaway? No sugar is a health food. Whether you choose raw slab sugar for its earthy flavor in sweet potato soup or white sugar for baking, moderation remains the key.
For those seeking to reduce sugar intake without sacrificing taste, the council recommends exploring natural sweeteners like fruit or using smaller amounts of intensely flavored sugars such as dark brown sugar or molasses. And for anyone relying on sugar for iron or calcium, the message is clear: look elsewhere—leafy greens, legumes, and fortified foods are far better sources.
As Hong Kong’s food culture continues to embrace both tradition and science, this investigation reminds us that even the most cherished pantry staples deserve a second look. The next time you reach for that bag of “healthy” brown sugar, remember: it’s still sugar. Enjoy it, but don’t fool yourself into thinking it’s a vitamin pill.